diff --git a/src/main/java/com/project/mapdagu/domain/member/controller/MemberController.java b/src/main/java/com/project/mapdagu/domain/member/controller/MemberController.java
index b6f5edc..11b4c46 100644
--- a/src/main/java/com/project/mapdagu/domain/member/controller/MemberController.java
+++ b/src/main/java/com/project/mapdagu/domain/member/controller/MemberController.java
@@ -2,8 +2,10 @@
 
 import com.project.mapdagu.common.dto.ResponseDto;
 import com.project.mapdagu.domain.member.dto.request.MemberUpdateInfoRequestDto;
+import com.project.mapdagu.domain.member.dto.request.MemberUserNameRequestDto;
 import com.project.mapdagu.domain.member.dto.response.MemberReadInfoResponseDto;
 import com.project.mapdagu.domain.member.dto.response.MemberReadMainResponseDto;
+import com.project.mapdagu.domain.member.dto.response.MemberUserNameResponseDto;
 import com.project.mapdagu.domain.member.service.MemberService;
 import com.project.mapdagu.error.dto.ErrorResponse;
 import io.swagger.v3.oas.annotations.Operation;
@@ -64,4 +66,16 @@ public ResponseEntity<MemberReadMainResponseDto> readMainInfo(@AuthenticationPri
         MemberReadMainResponseDto responseDto = memberService.readMainInfo(loginUser.getUsername());
         return ResponseDto.ok(responseDto);
     }
+
+    @Operation(summary = "회원 정보 수정", description = "회원 정보를 수정합니다.",
+            responses = {
+                    @ApiResponse(responseCode = "204", description = "회원 정보 수정 성공")
+                    , @ApiResponse(responseCode = "401", description = "인증에 실패했습니다.")
+                    , @ApiResponse(responseCode = "404", description = "1. 해당 회원을 찾을 수 없습니다. /t/n 2. 현재 사용자 이름과 동일합니다. /t/n 3. 이미 존재하는 사용자 이름입니다.", content = @Content(schema = @Schema(implementation = ErrorResponse.class)))
+            })
+    @PostMapping("/userName/isDuplicated")
+    public ResponseEntity<MemberUserNameResponseDto> checkUserName(@RequestBody MemberUserNameRequestDto requestDto) {
+        MemberUserNameResponseDto responseDto = memberService.checkUserName(requestDto);
+        return ResponseDto.ok(responseDto);
+    }
 }
diff --git a/src/main/java/com/project/mapdagu/domain/member/dto/request/MemberUserNameRequestDto.java b/src/main/java/com/project/mapdagu/domain/member/dto/request/MemberUserNameRequestDto.java
new file mode 100644
index 0000000..4df1b57
--- /dev/null
+++ b/src/main/java/com/project/mapdagu/domain/member/dto/request/MemberUserNameRequestDto.java
@@ -0,0 +1,4 @@
+package com.project.mapdagu.domain.member.dto.request;
+
+public record MemberUserNameRequestDto(String userName) {
+}
diff --git a/src/main/java/com/project/mapdagu/domain/member/dto/response/MemberUserNameResponseDto.java b/src/main/java/com/project/mapdagu/domain/member/dto/response/MemberUserNameResponseDto.java
new file mode 100644
index 0000000..fb6c766
--- /dev/null
+++ b/src/main/java/com/project/mapdagu/domain/member/dto/response/MemberUserNameResponseDto.java
@@ -0,0 +1,8 @@
+package com.project.mapdagu.domain.member.dto.response;
+
+public record MemberUserNameResponseDto(Boolean isDuplicated) {
+
+    public static MemberUserNameResponseDto of(Boolean isDuplicated){
+        return new MemberUserNameResponseDto(isDuplicated);
+    }
+}
diff --git a/src/main/java/com/project/mapdagu/domain/member/service/MemberService.java b/src/main/java/com/project/mapdagu/domain/member/service/MemberService.java
index 82e98c3..a37d2fb 100644
--- a/src/main/java/com/project/mapdagu/domain/member/service/MemberService.java
+++ b/src/main/java/com/project/mapdagu/domain/member/service/MemberService.java
@@ -1,8 +1,10 @@
 package com.project.mapdagu.domain.member.service;
 
 import com.project.mapdagu.domain.member.dto.request.MemberUpdateInfoRequestDto;
+import com.project.mapdagu.domain.member.dto.request.MemberUserNameRequestDto;
 import com.project.mapdagu.domain.member.dto.response.MemberReadInfoResponseDto;
 import com.project.mapdagu.domain.member.dto.response.MemberReadMainResponseDto;
+import com.project.mapdagu.domain.member.dto.response.MemberUserNameResponseDto;
 import com.project.mapdagu.domain.member.entity.Member;
 import com.project.mapdagu.domain.member.repository.MemberRepository;
 import com.project.mapdagu.error.ErrorCode;
@@ -36,4 +38,10 @@ public MemberReadMainResponseDto readMainInfo(String email) {
         MemberReadMainResponseDto response = MemberReadMainResponseDto.of(member.getUserName(), member.getLevel(), member.getImageNum());
         return response;
     }
+
+    public MemberUserNameResponseDto checkUserName(MemberUserNameRequestDto requestDto) {
+        Boolean isDuplicated = memberRepository.existsByUserName(requestDto.userName());
+        MemberUserNameResponseDto response = MemberUserNameResponseDto.of(isDuplicated);
+        return response;
+    }
 }