diff --git a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/AppAuthApi.java b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/AppAuthApi.java
index 24e04d2c..36878533 100644
--- a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/AppAuthApi.java
+++ b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/AppAuthApi.java
@@ -21,7 +21,7 @@ public interface AppAuthApi {
     @Operation(summary = "OAuth 로그인",
         description = """
             provider(현재 kconnect)에서 받은 code·codeVerifier·redirectUri로 로그인한다.
-            처음 로그인하면 회원이 만들어진다. termsAgreementRequired가 true면 필수 약관 동의가 필요하다.""")
+            처음 로그인하면 회원이 만들어진다. signUpRequired가 true면 회원가입(전화번호·필수 약관 동의)이 필요하다.""")
     @ApiErrorCode(type = CommonErrorCode.class, codes = {"INVALID_INPUT"})
     @ApiErrorCode(type = OAuthErrorCode.class, codes = {
         "UNSUPPORTED_OAUTH_PROVIDER",
diff --git a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/response/OAuthLoginResponse.java b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/response/OAuthLoginResponse.java
index 3b26ba62..6525bd93 100644
--- a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/response/OAuthLoginResponse.java
+++ b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/response/OAuthLoginResponse.java
@@ -1,9 +1,10 @@
 package kr.ac.kookmin.stream.api.app.core.auth.response;
 
 /**
- * @param termsAgreementRequired 필수 약관에 아직 동의하지 않았으면 true. 앱은 이 값으로 약관 화면을 띄운다
+ * @param signUpRequired 회원가입(전화번호·필수 약관 동의)을 마치지 않았으면 true. 앱은 이 값으로 회원가입 화면을 띄운다
  */
 public record OAuthLoginResponse(
     String accessToken,
-    boolean termsAgreementRequired
+    String name,
+    boolean signUpRequired
 ) {}
diff --git a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/usecase/OAuthLoginUseCase.java b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/usecase/OAuthLoginUseCase.java
index 1f887967..a530c56f 100644
--- a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/usecase/OAuthLoginUseCase.java
+++ b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/auth/usecase/OAuthLoginUseCase.java
@@ -7,7 +7,6 @@
 import kr.ac.kookmin.stream.member.domain.member.domain.Member;
 import kr.ac.kookmin.stream.member.domain.member.domain.MemberProfileCommand;
 import kr.ac.kookmin.stream.member.domain.member.service.MemberService;
-import kr.ac.kookmin.stream.member.domain.member.service.MemberTermService;
 import kr.ac.kookmin.stream.security.AuthTokenIssuer;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Component;
@@ -24,7 +23,6 @@ public class OAuthLoginUseCase {
 
     private final OAuthService oauthService;
     private final MemberService memberService;
-    private final MemberTermService memberTermService;
     private final AuthTokenIssuer authTokenIssuer;
 
     public OAuthLoginResponse login(OAuthLoginCommand command) {
@@ -32,9 +30,9 @@ public OAuthLoginResponse login(OAuthLoginCommand command) {
         Member member = findOrRegister(userInfo);
 
         String accessToken = authTokenIssuer.issue(member.getId(), member.getRole(), member.getCouncilDepartment());
-        // 회원을 이번에 만들었는지가 아니라 동의 기록으로 판단한다. 가입 후 동의하지 않고 이탈한 회원도 다시 약관 화면을 본다
-        boolean termsAgreementRequired = !memberTermService.hasAgreedRequiredTerms(member.getId());
-        return new OAuthLoginResponse(accessToken, termsAgreementRequired);
+        // 회원을 이번에 만들었는지가 아니라 저장된 전화번호·동의 기록으로 판단한다. 회원가입 화면에서 이탈한 회원도 다시 가입 화면을 본다
+        boolean signUpRequired = !memberService.isSignedUp(member.getId());
+        return new OAuthLoginResponse(accessToken, member.getName(), signUpRequired);
     }
 
     private Member findOrRegister(OAuthUserInfo userInfo) {
diff --git a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/AppMemberApi.java b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/AppMemberApi.java
new file mode 100644
index 00000000..9fd73ee0
--- /dev/null
+++ b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/AppMemberApi.java
@@ -0,0 +1,31 @@
+package kr.ac.kookmin.stream.api.app.core.member;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import kr.ac.kookmin.stream.api.app.AppApiUser;
+import kr.ac.kookmin.stream.api.app.core.member.request.MemberSignUpRequest;
+import kr.ac.kookmin.stream.api.common.dto.ApiResponse;
+import kr.ac.kookmin.stream.api.common.openapi.ApiErrorCode;
+import kr.ac.kookmin.stream.common.CommonErrorCode;
+import kr.ac.kookmin.stream.member.domain.member.domain.MemberErrorCode;
+
+/**
+ * 학생 앱 회원 API의 문서 명세. 구현은 {@link AppMemberController}가 맡는다.
+ */
+@Tag(name = "회원", description = "학생 앱 회원가입")
+public interface AppMemberApi {
+
+    /** 회원가입. 로그인 응답의 signUpRequired가 true인 회원이 전화번호와 약관 동의 여부를 등록한다. */
+    @Operation(summary = "회원가입",
+        description = """
+            로그인한 회원의 전화번호와 약관 동의 여부를 저장한다.
+            전화번호는 하이픈을 넣어도 되고 빼도 된다. 필수 약관(PRIVACY_POLICY, TERMS_OF_SERVICE)에 모두 동의해야 한다.""")
+    @ApiErrorCode(type = CommonErrorCode.class, codes = {"INVALID_INPUT"})
+    @ApiErrorCode(type = MemberErrorCode.class, codes = {
+        "MEMBER_NOT_FOUND",
+        "REQUIRED_TERMS_NOT_AGREED",
+        "ALREADY_SIGNED_UP",
+        "PHONE_NUMBER_ALREADY_EXISTS"
+    })
+    ApiResponse<Void> signUp(AppApiUser apiUser, MemberSignUpRequest request);
+}
diff --git a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/AppMemberController.java b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/AppMemberController.java
new file mode 100644
index 00000000..b40c3a98
--- /dev/null
+++ b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/AppMemberController.java
@@ -0,0 +1,30 @@
+package kr.ac.kookmin.stream.api.app.core.member;
+
+import jakarta.validation.Valid;
+import kr.ac.kookmin.stream.api.app.AppApiUser;
+import kr.ac.kookmin.stream.api.app.core.member.request.MemberSignUpRequest;
+import kr.ac.kookmin.stream.api.common.dto.ApiResponse;
+import kr.ac.kookmin.stream.member.domain.member.service.MemberService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/v1/app/members")
+@RequiredArgsConstructor
+public class AppMemberController implements AppMemberApi {
+
+    private final MemberService memberService;
+
+    @Override
+    @PostMapping("/sign-up")
+    public ApiResponse<Void> signUp(
+        AppApiUser apiUser,
+        @Valid @RequestBody MemberSignUpRequest request
+    ) {
+        memberService.signUp(apiUser.userId(), request.toCommand());
+        return ApiResponse.success();
+    }
+}
diff --git a/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/request/MemberSignUpRequest.java b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/request/MemberSignUpRequest.java
new file mode 100644
index 00000000..04122980
--- /dev/null
+++ b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/request/MemberSignUpRequest.java
@@ -0,0 +1,51 @@
+package kr.ac.kookmin.stream.api.app.core.member.request;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotEmpty;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Pattern;
+import java.util.EnumMap;
+import java.util.List;
+import java.util.Map;
+import kr.ac.kookmin.stream.member.domain.member.domain.MemberSignUpCommand;
+import kr.ac.kookmin.stream.member.domain.member.domain.TermType;
+
+public record MemberSignUpRequest(
+    @NotBlank(message = "전화번호를 입력해 주세요.")
+    @Pattern(regexp = "^010-?\\d{4}-?\\d{4}$", message = "전화번호 형식이 올바르지 않습니다.")
+    String phoneNumber,
+
+    // 필수 약관 여부는 TermType이 정하므로 여기서는 동의 값을 강제하지 않는다
+    @NotEmpty(message = "약관 동의 여부를 입력해 주세요.")
+    @Valid
+    List<@NotNull(message = "약관 동의 항목이 비어 있습니다.") TermAgreementRequest> termAgreements
+) {
+
+    public MemberSignUpCommand toCommand() {
+        validateTermTypesNotDuplicated();
+
+        Map<TermType, Boolean> agreements = new EnumMap<>(TermType.class);
+        termAgreements.forEach(agreement -> agreements.put(agreement.termType(), agreement.agreed()));
+        return new MemberSignUpCommand(phoneNumber, agreements);
+    }
+
+    // 같은 약관이 두 번 오면 IllegalArgumentException → GlobalExceptionHandler가 INVALID_INPUT(400)으로 응답한다
+    private void validateTermTypesNotDuplicated() {
+        long distinctTermTypeCount = termAgreements.stream()
+            .map(TermAgreementRequest::termType)
+            .distinct()
+            .count();
+        if (distinctTermTypeCount != termAgreements.size()) {
+            throw new IllegalArgumentException("같은 약관의 동의 여부가 중복되었습니다.");
+        }
+    }
+
+    public record TermAgreementRequest(
+        @NotNull(message = "약관 종류를 입력해 주세요.")
+        TermType termType,
+
+        @NotNull(message = "약관 동의 여부를 입력해 주세요.")
+        Boolean agreed
+    ) {}
+}
diff --git a/api/common-api/src/main/java/kr/ac/kookmin/stream/api/common/GlobalExceptionHandler.java b/api/common-api/src/main/java/kr/ac/kookmin/stream/api/common/GlobalExceptionHandler.java
index 276fb937..2a0dc73a 100644
--- a/api/common-api/src/main/java/kr/ac/kookmin/stream/api/common/GlobalExceptionHandler.java
+++ b/api/common-api/src/main/java/kr/ac/kookmin/stream/api/common/GlobalExceptionHandler.java
@@ -11,6 +11,7 @@
 import org.slf4j.LoggerFactory;
 import org.slf4j.MDC;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.validation.FieldError;
 import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ExceptionHandler;
@@ -53,6 +54,15 @@ public ResponseEntity<ApiResponse<Void>> handleIllegalArgument(IllegalArgumentEx
             .body(ApiResponse.error(CommonErrorCode.INVALID_INPUT.name(), e.getMessage()));
     }
 
+    // JSON 문법 오류, enum에 없는 값 등 요청 본문을 읽지 못한 경우. 파서 메시지는 내부 타입 이름을 담고 있어 응답에는 넣지 않는다
+    @ExceptionHandler(HttpMessageNotReadableException.class)
+    public ResponseEntity<ApiResponse<Void>> handleNotReadable(HttpMessageNotReadableException e) {
+        log.warn("[requestId={}, userId={}] (INVALID_INPUT) {}",
+            MDC.get(REQUEST_ID), MDC.get(USER_ID), e.getMessage());
+        return ResponseEntity.status(CommonErrorCode.INVALID_INPUT.status())
+            .body(ApiResponse.error(CommonErrorCode.INVALID_INPUT.name(), "요청 본문 형식이 올바르지 않습니다."));
+    }
+
     @ExceptionHandler(Exception.class)
     public ResponseEntity<ApiResponse<Void>> handleInternal(Exception e) {
         log.error("[requestId={}, userId={}] {}",
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/Member.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/Member.java
index 261e9301..b273e031 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/Member.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/Member.java
@@ -20,13 +20,15 @@ public class Member {
     // 로그인 provider가 주는 학적 상태 원문(재학·휴학·졸업 등). 로그인 전 이관 회원은 null이다
     private String academicStatus;
     private String email;
+    // 회원가입 때 받는 휴대전화 번호(숫자만). 가입 전 회원과 이관 회원은 null이다
+    private String phoneNumber;
     private String fcmToken;
     private Role role;
     private CouncilDepartment councilDepartment;
 
     // 로그인으로 처음 가입하는 회원. 운영진 권한·학생회 부서는 가입 뒤 따로 부여한다
     public static Member create(String studentId, String name, Department department, String academicStatus) {
-        return new Member(null, studentId, name, department, academicStatus, null, null, Role.STUDENT, null);
+        return new Member(null, studentId, name, department, academicStatus, null, null, null, Role.STUDENT, null);
     }
 
     public static Member of(
@@ -36,11 +38,13 @@ public static Member of(
         Department department,
         String academicStatus,
         String email,
+        String phoneNumber,
         String fcmToken,
         Role role,
         CouncilDepartment councilDepartment
     ) {
-        return new Member(id, studentId, name, department, academicStatus, email, fcmToken, role, councilDepartment);
+        return new Member(
+            id, studentId, name, department, academicStatus, email, phoneNumber, fcmToken, role, councilDepartment);
     }
 
     // 로그인할 때마다 provider의 최신 이름·학부·학적 상태로 갱신한다. 바뀐 값이 있으면 true를 돌려준다
@@ -55,4 +59,12 @@ public boolean updateProfile(String name, Department department, String academic
         this.academicStatus = academicStatus;
         return true;
     }
+
+    public void registerPhoneNumber(String phoneNumber) {
+        this.phoneNumber = phoneNumber;
+    }
+
+    public boolean hasPhoneNumber() {
+        return phoneNumber != null;
+    }
 }
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberErrorCode.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberErrorCode.java
index 1bfc9911..9b1d9695 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberErrorCode.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberErrorCode.java
@@ -12,7 +12,10 @@
 public enum MemberErrorCode implements ErrorCode {
 
     MEMBER_NOT_FOUND(ErrorStatus.NOT_FOUND, "회원을 찾을 수 없습니다."),
-    DEPARTMENT_NOT_ALLOWED(ErrorStatus.FORBIDDEN, "소프트웨어융합대학 학생만 이용할 수 있습니다.");
+    DEPARTMENT_NOT_ALLOWED(ErrorStatus.FORBIDDEN, "소프트웨어융합대학 학생만 이용할 수 있습니다."),
+    REQUIRED_TERMS_NOT_AGREED(ErrorStatus.BAD_REQUEST, "필수 약관에 모두 동의해 주세요."),
+    ALREADY_SIGNED_UP(ErrorStatus.CONFLICT, "이미 회원가입을 마쳤습니다."),
+    PHONE_NUMBER_ALREADY_EXISTS(ErrorStatus.CONFLICT, "이미 사용 중인 전화번호입니다.");
 
     private final int status;
     private final String message;
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberSignUpCommand.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberSignUpCommand.java
new file mode 100644
index 00000000..3c89a5f8
--- /dev/null
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberSignUpCommand.java
@@ -0,0 +1,16 @@
+package kr.ac.kookmin.stream.member.domain.member.domain;
+
+import java.util.Map;
+
+/**
+ * 회원가입 요청. 전화번호는 하이픈을 지운 숫자만 담는다. 중복 검사와 저장이 같은 형식을 쓰게 하기 위함이다.
+ */
+public record MemberSignUpCommand(
+    String phoneNumber,
+    Map<TermType, Boolean> termAgreements
+) {
+
+    public MemberSignUpCommand {
+        phoneNumber = phoneNumber.replace("-", "");
+    }
+}
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberTermAgreement.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberTermAgreement.java
index e330dc6e..291605e2 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberTermAgreement.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberTermAgreement.java
@@ -28,4 +28,19 @@ public static MemberTermAgreement of(
     ) {
         return new MemberTermAgreement(id, memberId, termType, termVersion, agreed, agreedAt);
     }
+
+    // 현재 약관 버전으로 동의 기록을 만든다. 동의하지 않았으면 동의 시각은 null이다
+    public static MemberTermAgreement create(Long memberId, TermType termType, boolean agreed, LocalDateTime now) {
+        return new MemberTermAgreement(null, memberId, termType, termType.version(), agreed, agreed ? now : null);
+    }
+
+    // 이미 기록이 있는 약관은 새 행을 만들지 않고 현재 버전으로 덮어쓴다. 버전과 동의 여부가 그대로면 최초 동의 시각을 지키도록 건너뛴다
+    public void update(boolean agreed, LocalDateTime now) {
+        if (termType.version().equals(this.termVersion) && this.agreed == agreed) {
+            return;
+        }
+        this.termVersion = termType.version();
+        this.agreed = agreed;
+        this.agreedAt = agreed ? now : null;
+    }
 }
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/TermType.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/TermType.java
index a70eb1ce..cd663d64 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/TermType.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/TermType.java
@@ -10,9 +10,12 @@
 @AllArgsConstructor(access = AccessLevel.PRIVATE)
 public enum TermType {
 
-    PRIVACY_POLICY(true),     // 개인정보 이용 동의
-    TERMS_OF_SERVICE(true);   // 서비스 이용 약관 동의
+    PRIVACY_POLICY(true, "v1"),     // 개인정보 이용 동의
+    TERMS_OF_SERVICE(true, "v1");   // 서비스 이용 약관 동의
 
     /** 가입 시 반드시 동의해야 하는 약관인지 여부 */
     private final boolean required;
+
+    /** 현재 약관 버전. 동의 기록에 함께 남긴다 */
+    private final String version;
 }
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/repository/MemberRepository.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/repository/MemberRepository.java
index c7e98d8e..d2e74f8a 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/repository/MemberRepository.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/repository/MemberRepository.java
@@ -7,6 +7,7 @@
 public interface MemberRepository {
     Optional<Member> findById(Long id);
     Optional<Member> findByStudentId(String studentId);
+    boolean existsByPhoneNumber(String phoneNumber);
     List<Member> findAllByIds(List<Long> ids);
     List<Long> searchIdsByKeyword(String keyword);
     Member save(Member member);
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/repository/MemberTermAgreementRepository.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/repository/MemberTermAgreementRepository.java
index 2ad7a2ec..86db290b 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/repository/MemberTermAgreementRepository.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/repository/MemberTermAgreementRepository.java
@@ -5,4 +5,5 @@
 
 public interface MemberTermAgreementRepository {
     List<MemberTermAgreement> findAllByMemberId(Long memberId);
+    void saveAll(List<MemberTermAgreement> agreements);
 }
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/MemberService.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/MemberService.java
index 7cd62f93..0c584bc8 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/MemberService.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/MemberService.java
@@ -4,6 +4,7 @@
 import java.util.Map;
 import kr.ac.kookmin.stream.member.domain.member.domain.Member;
 import kr.ac.kookmin.stream.member.domain.member.domain.MemberProfileCommand;
+import kr.ac.kookmin.stream.member.domain.member.domain.MemberSignUpCommand;
 
 public interface MemberService {
     Member getById(Long id);
@@ -12,4 +13,6 @@ public interface MemberService {
     List<Long> searchIdsByKeyword(String keyword);
     Member updateProfile(Long id, MemberProfileCommand command);
     Member registerOrUpdateByStudentId(MemberProfileCommand command);
+    Member signUp(Long memberId, MemberSignUpCommand command);
+    boolean isSignedUp(Long memberId);
 }
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/MemberTermService.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/MemberTermService.java
index 0abd77db..49f847d4 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/MemberTermService.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/MemberTermService.java
@@ -1,5 +1,9 @@
 package kr.ac.kookmin.stream.member.domain.member.service;
 
+import java.util.Map;
+import kr.ac.kookmin.stream.member.domain.member.domain.TermType;
+
 public interface MemberTermService {
     boolean hasAgreedRequiredTerms(Long memberId);
+    void agree(Long memberId, Map<TermType, Boolean> termAgreements);
 }
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/impl/MemberServiceImpl.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/impl/MemberServiceImpl.java
index b646fbe4..a8ad7c32 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/impl/MemberServiceImpl.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/impl/MemberServiceImpl.java
@@ -10,8 +10,10 @@
 import kr.ac.kookmin.stream.member.domain.member.domain.Member;
 import kr.ac.kookmin.stream.member.domain.member.domain.MemberErrorCode;
 import kr.ac.kookmin.stream.member.domain.member.domain.MemberProfileCommand;
+import kr.ac.kookmin.stream.member.domain.member.domain.MemberSignUpCommand;
 import kr.ac.kookmin.stream.member.domain.member.repository.MemberRepository;
 import kr.ac.kookmin.stream.member.domain.member.service.MemberService;
+import kr.ac.kookmin.stream.member.domain.member.service.MemberTermService;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
@@ -21,6 +23,7 @@
 class MemberServiceImpl implements MemberService {
 
     private final MemberRepository memberRepository;
+    private final MemberTermService memberTermService;
 
     @Override
     public Member getById(Long id) {
@@ -61,6 +64,46 @@ public Member registerOrUpdateByStudentId(MemberProfileCommand command) {
         return applyProfile(found.get(), command);
     }
 
+    // 전화번호 저장과 약관 동의를 한 트랜잭션으로 묶는다. 필수 약관에 동의하지 않으면 전화번호 저장도 롤백된다
+    @Override
+    @Transactional
+    public Member signUp(Long memberId, MemberSignUpCommand command) {
+        Member member = getById(memberId);
+        validateNotSignedUp(member);
+        validatePhoneNumberNotDuplicated(member, command.phoneNumber());
+
+        member.registerPhoneNumber(command.phoneNumber());
+        Member saved = memberRepository.save(member);
+        memberTermService.agree(memberId, command.termAgreements());
+        return saved;
+    }
+
+    @Override
+    public boolean isSignedUp(Long memberId) {
+        return isSignedUp(getById(memberId));
+    }
+
+    // 전화번호와 필수 약관 동의가 모두 있어야 가입을 마친 것으로 본다
+    private boolean isSignedUp(Member member) {
+        return member.hasPhoneNumber() && memberTermService.hasAgreedRequiredTerms(member.getId());
+    }
+
+    private void validateNotSignedUp(Member member) {
+        if (isSignedUp(member)) {
+            throw new BusinessException(MemberErrorCode.ALREADY_SIGNED_UP);
+        }
+    }
+
+    // 필수 약관이 늘어 다시 가입하는 회원은 자기 번호를 그대로 보낼 수 있으므로 같은 번호면 중복 검사를 건너뛴다
+    private void validatePhoneNumberNotDuplicated(Member member, String phoneNumber) {
+        if (phoneNumber.equals(member.getPhoneNumber())) {
+            return;
+        }
+        if (memberRepository.existsByPhoneNumber(phoneNumber)) {
+            throw new BusinessException(MemberErrorCode.PHONE_NUMBER_ALREADY_EXISTS);
+        }
+    }
+
     private Member register(MemberProfileCommand command) {
         Member member = Member.create(
             command.studentId(),
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/impl/MemberTermServiceImpl.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/impl/MemberTermServiceImpl.java
index 855ecb16..40a35149 100644
--- a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/impl/MemberTermServiceImpl.java
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/service/impl/MemberTermServiceImpl.java
@@ -1,14 +1,21 @@
 package kr.ac.kookmin.stream.member.domain.member.service.impl;
 
+import java.time.LocalDateTime;
 import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import java.util.function.Function;
 import java.util.stream.Collectors;
+import kr.ac.kookmin.stream.common.BusinessException;
+import kr.ac.kookmin.stream.member.domain.member.domain.MemberErrorCode;
 import kr.ac.kookmin.stream.member.domain.member.domain.MemberTermAgreement;
 import kr.ac.kookmin.stream.member.domain.member.domain.TermType;
 import kr.ac.kookmin.stream.member.domain.member.repository.MemberTermAgreementRepository;
 import kr.ac.kookmin.stream.member.domain.member.service.MemberTermService;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 @Service
 @RequiredArgsConstructor
@@ -26,4 +33,44 @@ public boolean hasAgreedRequiredTerms(Long memberId) {
             .filter(TermType::required)
             .allMatch(agreedTermTypes::contains);
     }
+
+    // 요청에 없는 약관은 동의하지 않은 것으로 보고 기록을 남기지 않는다
+    @Override
+    @Transactional
+    public void agree(Long memberId, Map<TermType, Boolean> termAgreements) {
+        validateRequiredTermsAgreed(termAgreements);
+
+        Map<TermType, MemberTermAgreement> existingAgreements = memberTermAgreementRepository.findAllByMemberId(memberId)
+            .stream()
+            .collect(Collectors.toMap(MemberTermAgreement::getTermType, Function.identity()));
+        LocalDateTime now = LocalDateTime.now();
+        List<MemberTermAgreement> agreements = termAgreements.entrySet().stream()
+            .map(entry -> toAgreement(memberId, entry.getKey(), entry.getValue(), existingAgreements, now))
+            .toList();
+        memberTermAgreementRepository.saveAll(agreements);
+    }
+
+    private void validateRequiredTermsAgreed(Map<TermType, Boolean> termAgreements) {
+        boolean requiredTermsAgreed = Arrays.stream(TermType.values())
+            .filter(TermType::required)
+            .allMatch(termType -> Boolean.TRUE.equals(termAgreements.get(termType)));
+        if (!requiredTermsAgreed) {
+            throw new BusinessException(MemberErrorCode.REQUIRED_TERMS_NOT_AGREED);
+        }
+    }
+
+    private MemberTermAgreement toAgreement(
+        Long memberId,
+        TermType termType,
+        boolean agreed,
+        Map<TermType, MemberTermAgreement> existingAgreements,
+        LocalDateTime now
+    ) {
+        MemberTermAgreement existing = existingAgreements.get(termType);
+        if (existing == null) {
+            return MemberTermAgreement.create(memberId, termType, agreed, now);
+        }
+        existing.update(agreed, now);
+        return existing;
+    }
 }
diff --git a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/common/ConstraintViolationUtil.java b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/common/ConstraintViolationUtil.java
new file mode 100644
index 00000000..d3760c26
--- /dev/null
+++ b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/common/ConstraintViolationUtil.java
@@ -0,0 +1,20 @@
+package kr.ac.kookmin.stream.db.common;
+
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+import org.hibernate.exception.ConstraintViolationException;
+import org.springframework.dao.DataIntegrityViolationException;
+
+/**
+ * DB 제약 위반 예외 판별 유틸.
+ */
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public final class ConstraintViolationUtil {
+
+    /** MySQL은 제약 이름 앞에 테이블명을 붙여 줄 수 있어 포함 여부로 비교한다. */
+    public static boolean isViolated(DataIntegrityViolationException e, String constraintName) {
+        return e.getCause() instanceof ConstraintViolationException violation
+            && violation.getConstraintName() != null
+            && violation.getConstraintName().contains(constraintName);
+    }
+}
diff --git a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/event/LockerApplicationRepositoryImpl.java b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/event/LockerApplicationRepositoryImpl.java
index 4c08e488..5363247b 100644
--- a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/event/LockerApplicationRepositoryImpl.java
+++ b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/event/LockerApplicationRepositoryImpl.java
@@ -4,11 +4,11 @@
 import java.util.Optional;
 import java.util.Set;
 import kr.ac.kookmin.stream.common.BusinessException;
+import kr.ac.kookmin.stream.db.common.ConstraintViolationUtil;
 import kr.ac.kookmin.stream.event.domain.locker.domain.LockerApplication;
 import kr.ac.kookmin.stream.event.domain.locker.domain.LockerErrorCode;
 import kr.ac.kookmin.stream.event.domain.locker.repository.LockerApplicationRepository;
 import lombok.RequiredArgsConstructor;
-import org.hibernate.exception.ConstraintViolationException;
 import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.stereotype.Repository;
 
@@ -49,17 +49,10 @@ public LockerApplication save(LockerApplication application) {
             return lockerApplicationJpaRepository.saveAndFlush(LockerApplicationJpaEntity.from(application))
                 .toDomain();
         } catch (DataIntegrityViolationException e) {
-            if (isViolated(e, LOCKER_UNIQUE_CONSTRAINT)) {
+            if (ConstraintViolationUtil.isViolated(e, LOCKER_UNIQUE_CONSTRAINT)) {
                 throw new BusinessException(LockerErrorCode.LOCKER_ALREADY_ASSIGNED);
             }
             throw e;
         }
     }
-
-    /** MySQL은 제약 이름 앞에 테이블명을 붙여 줄 수 있어 포함 여부로 비교한다. */
-    private boolean isViolated(DataIntegrityViolationException e, String constraintName) {
-        return e.getCause() instanceof ConstraintViolationException violation
-            && violation.getConstraintName() != null
-            && violation.getConstraintName().contains(constraintName);
-    }
 }
diff --git a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberJpaEntity.java b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberJpaEntity.java
index a3069ec3..2ea39bfc 100644
--- a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberJpaEntity.java
+++ b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberJpaEntity.java
@@ -17,8 +17,8 @@
 import lombok.NoArgsConstructor;
 
 @Entity
-// uk_members_active_student_id(V1)는 generated column active_student_id에 걸려 있다.
-// Entity에 매핑된 컬럼이 아니라 여기서는 선언하지 않는다.
+// uk_members_active_student_id(V1)·uk_members_active_phone_number(V16)는 generated column
+// active_student_id·active_phone_number에 걸려 있다. Entity에 매핑된 컬럼이 아니라 여기서는 선언하지 않는다.
 @Table(name = "members")
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
 public class MemberJpaEntity extends BaseSoftDeleteEntity {
@@ -43,6 +43,9 @@ public class MemberJpaEntity extends BaseSoftDeleteEntity {
 
     private String email;
 
+    @Column(name = "phone_number", length = 20)
+    private String phoneNumber;
+
     @Column(name = "fcm_token")
     private String fcmToken;
 
@@ -61,6 +64,7 @@ private MemberJpaEntity(Member member) {
         this.department = member.getDepartment();
         this.academicStatus = member.getAcademicStatus();
         this.email = member.getEmail();
+        this.phoneNumber = member.getPhoneNumber();
         this.fcmToken = member.getFcmToken();
         this.role = member.getRole();
         this.councilDepartment = member.getCouncilDepartment();
@@ -71,6 +75,7 @@ public static MemberJpaEntity from(Member member) {
     }
 
     public Member toDomain() {
-        return Member.of(id, studentId, name, department, academicStatus, email, fcmToken, role, councilDepartment);
+        return Member.of(
+            id, studentId, name, department, academicStatus, email, phoneNumber, fcmToken, role, councilDepartment);
     }
 }
diff --git a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberJpaRepository.java b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberJpaRepository.java
index 2877d272..a1b224b7 100644
--- a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberJpaRepository.java
+++ b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberJpaRepository.java
@@ -12,6 +12,8 @@ public interface MemberJpaRepository extends JpaRepository<MemberJpaEntity, Long
 
     Optional<MemberJpaEntity> findByStudentIdAndIsDeletedFalse(String studentId);
 
+    boolean existsByPhoneNumberAndIsDeletedFalse(String phoneNumber);
+
     List<MemberJpaEntity> findAllByIdInAndIsDeletedFalse(List<Long> ids);
 
     @Query("""
diff --git a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberRepositoryImpl.java b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberRepositoryImpl.java
index 89998df2..9996c87a 100644
--- a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberRepositoryImpl.java
+++ b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberRepositoryImpl.java
@@ -2,15 +2,21 @@
 
 import java.util.List;
 import java.util.Optional;
+import kr.ac.kookmin.stream.common.BusinessException;
+import kr.ac.kookmin.stream.db.common.ConstraintViolationUtil;
 import kr.ac.kookmin.stream.member.domain.member.domain.Member;
+import kr.ac.kookmin.stream.member.domain.member.domain.MemberErrorCode;
 import kr.ac.kookmin.stream.member.domain.member.repository.MemberRepository;
 import lombok.RequiredArgsConstructor;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.stereotype.Repository;
 
 @Repository
 @RequiredArgsConstructor
 public class MemberRepositoryImpl implements MemberRepository {
 
+    private static final String PHONE_NUMBER_UNIQUE_CONSTRAINT = "uk_members_active_phone_number";
+
     private final MemberJpaRepository memberJpaRepository;
 
     @Override
@@ -23,6 +29,11 @@ public Optional<Member> findByStudentId(String studentId) {
         return memberJpaRepository.findByStudentIdAndIsDeletedFalse(studentId).map(MemberJpaEntity::toDomain);
     }
 
+    @Override
+    public boolean existsByPhoneNumber(String phoneNumber) {
+        return memberJpaRepository.existsByPhoneNumberAndIsDeletedFalse(phoneNumber);
+    }
+
     @Override
     public List<Member> findAllByIds(List<Long> ids) {
         if (ids.isEmpty()) {
@@ -40,6 +51,14 @@ public List<Long> searchIdsByKeyword(String keyword) {
 
     @Override
     public Member save(Member member) {
-        return memberJpaRepository.save(MemberJpaEntity.from(member)).toDomain();
+        try {
+            // 동시 가입으로 중복 검사를 함께 통과한 경우 유니크 인덱스 위반을 이 자리에서 잡으려면 바로 반영해야 한다
+            return memberJpaRepository.saveAndFlush(MemberJpaEntity.from(member)).toDomain();
+        } catch (DataIntegrityViolationException e) {
+            if (ConstraintViolationUtil.isViolated(e, PHONE_NUMBER_UNIQUE_CONSTRAINT)) {
+                throw new BusinessException(MemberErrorCode.PHONE_NUMBER_ALREADY_EXISTS);
+            }
+            throw e;
+        }
     }
 }
diff --git a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberTermAgreementRepositoryImpl.java b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberTermAgreementRepositoryImpl.java
index 42d8f3b0..d65d7280 100644
--- a/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberTermAgreementRepositoryImpl.java
+++ b/infrastructure/db/src/main/java/kr/ac/kookmin/stream/db/member/MemberTermAgreementRepositoryImpl.java
@@ -18,4 +18,11 @@ public List<MemberTermAgreement> findAllByMemberId(Long memberId) {
             .map(MemberTermAgreementJpaEntity::toDomain)
             .toList();
     }
+
+    @Override
+    public void saveAll(List<MemberTermAgreement> agreements) {
+        memberTermAgreementJpaRepository.saveAll(agreements.stream()
+            .map(MemberTermAgreementJpaEntity::from)
+            .toList());
+    }
 }
diff --git a/infrastructure/db/src/main/resources/db/migration/V16__add_phone_number_to_members.sql b/infrastructure/db/src/main/resources/db/migration/V16__add_phone_number_to_members.sql
new file mode 100644
index 00000000..78870871
--- /dev/null
+++ b/infrastructure/db/src/main/resources/db/migration/V16__add_phone_number_to_members.sql
@@ -0,0 +1,10 @@
+-- 회원가입 때 받는 휴대전화 번호. 하이픈 없이 숫자만 저장한다(01012345678).
+-- 가입 전 회원과 기존(이관) 회원은 값이 없으므로 NULL을 허용한다.
+ALTER TABLE members
+    ADD COLUMN phone_number VARCHAR(20) NULL AFTER email;
+
+-- 활성 회원의 전화번호만 유니크 (탈퇴 후 같은 번호로 재가입 허용)
+ALTER TABLE members
+    ADD COLUMN active_phone_number VARCHAR(20)
+        GENERATED ALWAYS AS (IF(is_deleted = 0, phone_number, NULL)) VIRTUAL;
+CREATE UNIQUE INDEX uk_members_active_phone_number ON members (active_phone_number);