diff --git a/src/main/java/org/sopt/lequuServer/domain/member/service/MemberService.java b/src/main/java/org/sopt/lequuServer/domain/member/service/MemberService.java
index 8a311b4..564e4df 100644
--- a/src/main/java/org/sopt/lequuServer/domain/member/service/MemberService.java
+++ b/src/main/java/org/sopt/lequuServer/domain/member/service/MemberService.java
@@ -1,5 +1,10 @@
 package org.sopt.lequuServer.domain.member.service;
 
+import static org.sopt.lequuServer.global.exception.enums.ErrorType.INVALID_SOCIAL_ACCESS_TOKEN;
+import static org.sopt.lequuServer.global.exception.enums.ErrorType.INVALID_TOKEN_HEADER_ERROR;
+import static org.sopt.lequuServer.global.exception.enums.ErrorType.NOT_FOUND_MEMBER_ERROR;
+
+import java.util.List;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.sopt.lequuServer.domain.book.model.Book;
@@ -18,14 +23,11 @@
 import org.sopt.lequuServer.global.auth.jwt.TokenDto;
 import org.sopt.lequuServer.global.auth.security.UserAuthentication;
 import org.sopt.lequuServer.global.common.logging.LoggingMessage;
+import org.sopt.lequuServer.global.exception.enums.ErrorType;
 import org.sopt.lequuServer.global.exception.model.CustomException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
-import java.util.List;
-
-import static org.sopt.lequuServer.global.exception.enums.ErrorType.*;
-
 @Slf4j
 @Service
 @RequiredArgsConstructor
@@ -119,6 +121,9 @@ private static String parseTokenString(String tokenString) {
     @Transactional
     public MemberNicknameResponseDto setMemberNickname(Long memberId, MemberNicknameRequestDto request) {
         Member member = memberRepository.findByIdOrThrow(memberId);
+        if (member.getNickname().equals(request.nickname())) {
+            throw new CustomException(ErrorType.NICKNAME_DUP_ERROR);
+        }
         member.updateNickname(request.nickname().strip());
         return MemberNicknameResponseDto.of(memberId);
     }
diff --git a/src/main/java/org/sopt/lequuServer/global/exception/enums/ErrorType.java b/src/main/java/org/sopt/lequuServer/global/exception/enums/ErrorType.java
index 6caed3e..f6458f2 100644
--- a/src/main/java/org/sopt/lequuServer/global/exception/enums/ErrorType.java
+++ b/src/main/java/org/sopt/lequuServer/global/exception/enums/ErrorType.java
@@ -50,6 +50,12 @@ public enum ErrorType {
     NOT_FOUND_BOOK_ERROR(HttpStatus.NOT_FOUND, "존재하지 않는 레큐북입니다."),
     NOT_FOUND_STICKER_ERROR(HttpStatus.NOT_FOUND, "존재하지 않는 스티커입니다."),
 
+    /**
+     * 409 CONFLICT
+     */
+    NICKNAME_DUP_ERROR(HttpStatus.CONFLICT, "중복된 회원 닉네임입니다."),
+
+
     /**
      * 500 INTERNAL SERVER ERROR
      */