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
index a13b436c..795f63ea 100644
--- 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
@@ -5,6 +5,7 @@
 import kr.ac.kookmin.stream.api.app.AppApiUser;
 import kr.ac.kookmin.stream.api.app.core.member.request.FcmTokenUpdateRequest;
 import kr.ac.kookmin.stream.api.app.core.member.request.MemberSignUpRequest;
+import kr.ac.kookmin.stream.api.app.core.member.request.PhoneNumberUpdateRequest;
 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;
@@ -13,7 +14,7 @@
 /**
  * 학생 앱 회원 API의 문서 명세. 구현은 {@link AppMemberController}가 맡는다.
  */
-@Tag(name = "회원", description = "학생 앱 회원가입·FCM 토큰 등록")
+@Tag(name = "회원", description = "학생 앱 회원가입·FCM 토큰 등록·전화번호 변경")
 public interface AppMemberApi {
 
     /** 회원가입. 로그인 응답의 signUpRequired가 true인 회원이 전화번호와 약관 동의 여부를 등록한다. */
@@ -38,4 +39,13 @@ public interface AppMemberApi {
     @ApiErrorCode(type = CommonErrorCode.class, codes = {"INVALID_INPUT"})
     @ApiErrorCode(type = MemberErrorCode.class, codes = {"MEMBER_NOT_FOUND"})
     ApiResponse<Void> updateFcmToken(AppApiUser apiUser, FcmTokenUpdateRequest request);
+
+    /** 전화번호 변경. 로그인한 회원이 자기 전화번호를 바꾼다. */
+    @Operation(summary = "전화번호 변경",
+        description = """
+            로그인한 회원의 전화번호를 바꾼다. 전화번호는 하이픈을 넣어도 되고 빼도 된다.
+            지금 쓰는 번호와 같으면 바꾸지 않고 성공으로 응답한다. 다른 회원이 쓰는 번호로는 바꿀 수 없다.""")
+    @ApiErrorCode(type = CommonErrorCode.class, codes = {"INVALID_INPUT"})
+    @ApiErrorCode(type = MemberErrorCode.class, codes = {"MEMBER_NOT_FOUND", "PHONE_NUMBER_ALREADY_EXISTS"})
+    ApiResponse<Void> updatePhoneNumber(AppApiUser apiUser, PhoneNumberUpdateRequest 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
index 67d0ae93..1cfe25e3 100644
--- 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
@@ -4,6 +4,7 @@
 import kr.ac.kookmin.stream.api.app.AppApiUser;
 import kr.ac.kookmin.stream.api.app.core.member.request.FcmTokenUpdateRequest;
 import kr.ac.kookmin.stream.api.app.core.member.request.MemberSignUpRequest;
+import kr.ac.kookmin.stream.api.app.core.member.request.PhoneNumberUpdateRequest;
 import kr.ac.kookmin.stream.api.common.dto.ApiResponse;
 import kr.ac.kookmin.stream.member.domain.member.service.MemberService;
 import lombok.RequiredArgsConstructor;
@@ -39,4 +40,14 @@ public ApiResponse<Void> updateFcmToken(
         memberService.updateFcmToken(apiUser.userId(), request.fcmToken());
         return ApiResponse.success();
     }
+
+    @Override
+    @PatchMapping("/me/phone-number")
+    public ApiResponse<Void> updatePhoneNumber(
+        AppApiUser apiUser,
+        @Valid @RequestBody PhoneNumberUpdateRequest request
+    ) {
+        memberService.updatePhoneNumber(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/PhoneNumberUpdateRequest.java b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/request/PhoneNumberUpdateRequest.java
new file mode 100644
index 00000000..363291a4
--- /dev/null
+++ b/api/app-api/src/main/java/kr/ac/kookmin/stream/api/app/core/member/request/PhoneNumberUpdateRequest.java
@@ -0,0 +1,17 @@
+package kr.ac.kookmin.stream.api.app.core.member.request;
+
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.Pattern;
+import kr.ac.kookmin.stream.member.domain.member.domain.MemberPhoneNumberUpdateCommand;
+
+public record PhoneNumberUpdateRequest(
+    // 가입 때 받은 번호와 형식이 달라지지 않도록 MemberSignUpRequest와 같은 규칙으로 검증한다
+    @NotBlank(message = "전화번호를 입력해 주세요.")
+    @Pattern(regexp = "^010-?\\d{4}-?\\d{4}$", message = "전화번호 형식이 올바르지 않습니다.")
+    String phoneNumber
+) {
+
+    public MemberPhoneNumberUpdateCommand toCommand() {
+        return new MemberPhoneNumberUpdateCommand(phoneNumber);
+    }
+}
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 158bc599..3f666e53 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
@@ -68,6 +68,15 @@ public boolean hasPhoneNumber() {
         return phoneNumber != null;
     }
 
+    // 회원이 바꾼 전화번호로 갱신한다. 바뀐 값이 있으면 true를 돌려준다
+    public boolean updatePhoneNumber(String phoneNumber) {
+        if (Objects.equals(this.phoneNumber, phoneNumber)) {
+            return false;
+        }
+        this.phoneNumber = phoneNumber;
+        return true;
+    }
+
     // 앱이 Firebase에서 받은 등록 토큰으로 바꾼다. 바뀐 값이 있으면 true를 돌려준다
     public boolean updateFcmToken(String fcmToken) {
         if (Objects.equals(this.fcmToken, fcmToken)) {
diff --git a/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberPhoneNumberUpdateCommand.java b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberPhoneNumberUpdateCommand.java
new file mode 100644
index 00000000..4e85bc69
--- /dev/null
+++ b/core/domain/member/src/main/java/kr/ac/kookmin/stream/member/domain/member/domain/MemberPhoneNumberUpdateCommand.java
@@ -0,0 +1,11 @@
+package kr.ac.kookmin.stream.member.domain.member.domain;
+
+/**
+ * 전화번호 변경 요청. 전화번호는 하이픈을 지운 숫자만 담는다. 중복 검사와 저장이 같은 형식을 쓰게 하기 위함이다.
+ */
+public record MemberPhoneNumberUpdateCommand(String phoneNumber) {
+
+    public MemberPhoneNumberUpdateCommand {
+        phoneNumber = phoneNumber.replace("-", "");
+    }
+}
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 39d1a0fd..b0cded3e 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
@@ -3,6 +3,7 @@
 import java.util.List;
 import java.util.Map;
 import kr.ac.kookmin.stream.member.domain.member.domain.Member;
+import kr.ac.kookmin.stream.member.domain.member.domain.MemberPhoneNumberUpdateCommand;
 import kr.ac.kookmin.stream.member.domain.member.domain.MemberProfileCommand;
 import kr.ac.kookmin.stream.member.domain.member.domain.MemberSignUpCommand;
 
@@ -16,4 +17,5 @@ public interface MemberService {
     Member signUp(Long memberId, MemberSignUpCommand command);
     boolean isSignedUp(Long memberId);
     void updateFcmToken(Long memberId, String fcmToken);
+    void updatePhoneNumber(Long memberId, MemberPhoneNumberUpdateCommand command);
 }
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 f6bdf2d2..16babadf 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
@@ -9,6 +9,7 @@
 import kr.ac.kookmin.stream.member.domain.member.domain.Department;
 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.MemberPhoneNumberUpdateCommand;
 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;
@@ -95,6 +96,16 @@ public void updateFcmToken(Long memberId, String fcmToken) {
         }
     }
 
+    @Override
+    @Transactional
+    public void updatePhoneNumber(Long memberId, MemberPhoneNumberUpdateCommand command) {
+        Member member = getById(memberId);
+        validatePhoneNumberNotDuplicated(member, command.phoneNumber());
+        if (member.updatePhoneNumber(command.phoneNumber())) {
+            memberRepository.save(member);
+        }
+    }
+
     // 전화번호와 필수 약관 동의가 모두 있어야 가입을 마친 것으로 본다
     private boolean isSignedUp(Member member) {
         return member.hasPhoneNumber() && memberTermService.hasAgreedRequiredTerms(member.getId());
@@ -106,7 +117,7 @@ private void validateNotSignedUp(Member member) {
         }
     }
 
-    // 필수 약관이 늘어 다시 가입하는 회원은 자기 번호를 그대로 보낼 수 있으므로 같은 번호면 중복 검사를 건너뛴다
+    // 필수 약관이 늘어 다시 가입하거나 같은 번호로 변경을 요청하는 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;