diff --git a/src/main/java/com/example/spot/api/code/status/ErrorStatus.java b/src/main/java/com/example/spot/api/code/status/ErrorStatus.java
index 3f9e3ed8..77a337f4 100644
--- a/src/main/java/com/example/spot/api/code/status/ErrorStatus.java
+++ b/src/main/java/com/example/spot/api/code/status/ErrorStatus.java
@@ -55,6 +55,7 @@ public enum ErrorStatus implements BaseErrorCode {
     _UNABLE_TO_SEND_VERIFICATION_CODE(HttpStatus.BAD_REQUEST, "AA4017", "인증 코드를 전송할 수 없습니다."),
     _UNABLE_TO_SEND_EMAIL(HttpStatus.BAD_REQUEST, "AA4018", "이메일을 전송할 수 없습니다."),
     _UNABLE_TO_LOAD_MAIL_FORM(HttpStatus.INTERNAL_SERVER_ERROR, "AA4019", "이메일 인증 폼을 불러올 수 없습니다."),
+    _MEMBER_LOGIN_ID_ALREADY_EXISTS(HttpStatus.BAD_REQUEST, "AA4020", "해당 로그인 아이디로 가입한 회원이 이미 존재합니다."),
 
     //스터디 관련 에러
     _STUDY_NOT_FOUND(HttpStatus.NOT_FOUND, "STUDY4001", "스터디를 찾을 수 없습니다."),
diff --git a/src/main/java/com/example/spot/service/auth/AuthService.java b/src/main/java/com/example/spot/service/auth/AuthService.java
index 123729a7..02f2bc9f 100644
--- a/src/main/java/com/example/spot/service/auth/AuthService.java
+++ b/src/main/java/com/example/spot/service/auth/AuthService.java
@@ -15,7 +15,7 @@ public interface AuthService {
     // 리프레시 토큰을 사용하여 새로운 액세스 토큰을 발급
     TokenDTO reissueToken(String refreshToken);
 
-    MemberResponseDTO.MemberUpdateDTO signUpAndPartialUpdate(String nickname, Boolean personalInfo, Boolean idInfo);
+    MemberResponseDTO.MemberInfoCreationDTO signUpAndPartialUpdate(String nickname, Boolean personalInfo, Boolean idInfo);
 
     void authorizeWithNaver(HttpServletRequest request, HttpServletResponse response);
 
diff --git a/src/main/java/com/example/spot/service/auth/AuthServiceImpl.java b/src/main/java/com/example/spot/service/auth/AuthServiceImpl.java
index c60fa44d..7bb30ab1 100644
--- a/src/main/java/com/example/spot/service/auth/AuthServiceImpl.java
+++ b/src/main/java/com/example/spot/service/auth/AuthServiceImpl.java
@@ -37,7 +37,6 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
-import com.fasterxml.jackson.core.JsonProcessingException;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import lombok.RequiredArgsConstructor;
@@ -113,7 +112,7 @@ public TokenDTO reissueToken(String refreshToken) {
 /* ----------------------------- 공통 회원 관리 API ------------------------------------- */
 
     @Override
-    public MemberResponseDTO.MemberUpdateDTO signUpAndPartialUpdate(String nickname, Boolean personalInfo, Boolean idInfo) {
+    public MemberResponseDTO.MemberInfoCreationDTO signUpAndPartialUpdate(String nickname, Boolean personalInfo, Boolean idInfo) {
 
         // Authorization
         Long memberId = SecurityUtils.getCurrentUserId();
@@ -124,10 +123,7 @@ public MemberResponseDTO.MemberUpdateDTO signUpAndPartialUpdate(String nickname,
         member.updateTerm(personalInfo, idInfo);
         member = memberRepository.save(member);
 
-        return MemberResponseDTO.MemberUpdateDTO.builder()
-                .memberId(memberId)
-                .updatedAt(member.getUpdatedAt())
-                .build();
+        return MemberResponseDTO.MemberInfoCreationDTO.toDTO(member);
     }
 
 /* ----------------------------- 네이버 소셜로그인 API ------------------------------------- */
@@ -365,6 +361,9 @@ public MemberResponseDTO.MemberSignInDTO signUp(MemberRequestDTO.SignUpDTO signU
         if (memberRepository.existsByEmail(signUpDTO.getEmail())) {
             throw new MemberHandler(ErrorStatus._MEMBER_EMAIL_ALREADY_EXISTS);
         }
+        if (memberRepository.existsByLoginId(signUpDTO.getLoginId())) {
+            throw new MemberHandler(ErrorStatus._MEMBER_LOGIN_ID_ALREADY_EXISTS);
+        }
         if (!signUpDTO.getPassword().equals(signUpDTO.getPwCheck())) {
             throw new MemberHandler(ErrorStatus._MEMBER_PW_AND_PW_CHECK_DO_NOT_MATCH);
         }
diff --git a/src/main/java/com/example/spot/web/controller/AuthController.java b/src/main/java/com/example/spot/web/controller/AuthController.java
index 78058df8..32ebf603 100644
--- a/src/main/java/com/example/spot/web/controller/AuthController.java
+++ b/src/main/java/com/example/spot/web/controller/AuthController.java
@@ -54,13 +54,13 @@ public ApiResponse<TokenDTO> reissueToken(HttpServletRequest request,
             * Request Params : String nickname, Boolean personalInfo, Boolean idInfo
             * Response Body : Long memberId, LocalDateTime updatedAt
             """)
-    @GetMapping("/sign-up/update")
-    public ApiResponse<MemberResponseDTO.MemberUpdateDTO> signUpAndPartialUpdate(
+    @PostMapping("/sign-up/update")
+    public ApiResponse<MemberResponseDTO.MemberInfoCreationDTO> signUpAndPartialUpdate(
             @RequestParam @TextLength(max = 8) String nickname,
             @RequestParam Boolean personalInfo,
             @RequestParam Boolean idInfo) {
-        MemberResponseDTO.MemberUpdateDTO memberUpdateDTO = authService.signUpAndPartialUpdate(nickname, personalInfo, idInfo);
-        return ApiResponse.onSuccess(SuccessStatus._MEMBER_UPDATED, memberUpdateDTO);
+        MemberResponseDTO.MemberInfoCreationDTO memberInfoCreationDTO = authService.signUpAndPartialUpdate(nickname, personalInfo, idInfo);
+        return ApiResponse.onSuccess(SuccessStatus._MEMBER_UPDATED, memberInfoCreationDTO);
     }
 
 /* ----------------------------- 네이버 소셜로그인 API ------------------------------------- */
diff --git a/src/main/java/com/example/spot/web/dto/member/MemberResponseDTO.java b/src/main/java/com/example/spot/web/dto/member/MemberResponseDTO.java
index 9d0c7d9e..2048de1e 100644
--- a/src/main/java/com/example/spot/web/dto/member/MemberResponseDTO.java
+++ b/src/main/java/com/example/spot/web/dto/member/MemberResponseDTO.java
@@ -13,6 +13,25 @@
 @Getter
 public class MemberResponseDTO {
 
+    @Getter
+    @RequiredArgsConstructor(access = AccessLevel.PRIVATE)
+    @Builder(access = AccessLevel.PRIVATE)
+    public static class MemberInfoCreationDTO {
+        private final String name;
+        private final String email;
+        private final Boolean idInfo;
+        private final Boolean personalInfo;
+
+        public static MemberInfoCreationDTO toDTO(Member member) {
+            return MemberInfoCreationDTO.builder()
+                    .name(member.getName())
+                    .email(member.getEmail())
+                    .idInfo(member.getIdInfo())
+                    .personalInfo(member.getPersonalInfo())
+                    .build();
+        }
+    }
+
     @Getter
     @RequiredArgsConstructor(access = AccessLevel.PRIVATE)
     @Builder(access = AccessLevel.PRIVATE)