diff --git a/src/main/java/com/sajang/devracebackend/controller/AuthController.java b/src/main/java/com/sajang/devracebackend/controller/AuthController.java
index 3b7eeeb..610abc4 100644
--- a/src/main/java/com/sajang/devracebackend/controller/AuthController.java
+++ b/src/main/java/com/sajang/devracebackend/controller/AuthController.java
@@ -1,10 +1,13 @@
 package com.sajang.devracebackend.controller;
 
+import com.sajang.devracebackend.dto.auth.ReissueRequestDto;
 import com.sajang.devracebackend.dto.auth.SignupRequestDto;
 import com.sajang.devracebackend.dto.auth.SignupResponseDto;
+import com.sajang.devracebackend.dto.auth.TokenDto;
 import com.sajang.devracebackend.response.ResponseCode;
 import com.sajang.devracebackend.response.ResponseData;
 import com.sajang.devracebackend.service.AuthService;
+import com.sajang.devracebackend.service.TokenService;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import lombok.RequiredArgsConstructor;
@@ -24,6 +27,7 @@
 public class AuthController {
 
     private final AuthService authService;
+    private final TokenService tokenService;
 
 
     @PostMapping(value = "/signup", consumes = MediaType.MULTIPART_FORM_DATA_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
@@ -35,4 +39,11 @@ public ResponseEntity<ResponseData<SignupResponseDto>> signup(
         SignupResponseDto signupResponseDto = authService.signup(imageFile, signupRequestDto);
         return ResponseData.toResponseEntity(ResponseCode.CREATED_USER, signupResponseDto);  // 이 reponseDto 내에 새로운 JWT Access 토큰이 들어있음. 이후 앞으로는 이걸로 헤더에 장착해야함.
     }
+
+    @PostMapping("/reissue")
+    @Operation(summary = "JWT Access Token 재발급(로그인 유지) [jwt X]")
+    public ResponseEntity<ResponseData<TokenDto>> reissue(@RequestBody ReissueRequestDto reissueRequestDto) {
+        TokenDto tokenDto = tokenService.reissue(reissueRequestDto);
+        return ResponseData.toResponseEntity(ResponseCode.REISSUE_SUCCESS, tokenDto);
+    }
 }
diff --git a/src/main/java/com/sajang/devracebackend/dto/auth/ReissueRequestDto.java b/src/main/java/com/sajang/devracebackend/dto/auth/ReissueRequestDto.java
new file mode 100644
index 0000000..43bc046
--- /dev/null
+++ b/src/main/java/com/sajang/devracebackend/dto/auth/ReissueRequestDto.java
@@ -0,0 +1,12 @@
+package com.sajang.devracebackend.dto.auth;
+
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class ReissueRequestDto {
+
+    private String accessToken;
+    private String refreshToken;
+}
diff --git a/src/main/java/com/sajang/devracebackend/response/GlobalExceptionHandler.java b/src/main/java/com/sajang/devracebackend/response/GlobalExceptionHandler.java
index 4491fd4..68bb7b0 100644
--- a/src/main/java/com/sajang/devracebackend/response/GlobalExceptionHandler.java
+++ b/src/main/java/com/sajang/devracebackend/response/GlobalExceptionHandler.java
@@ -71,6 +71,12 @@ public ResponseEntity handleRoomBadRequestException(RoomBadRequestException ex)
         return ResponseData.toResponseEntity(ResponseCode.BAD_REQUEST_ROOM);
     }
 
+    @ExceptionHandler(TokenBadRequestException.class)
+    public ResponseEntity handleTokenBadRequestException(TokenBadRequestException ex) {
+        log.error(ex.getErrorStatus() + " " + ex.getErrorMessage() + "\n" + "==> error_messege / " + ex.getMessage());
+        return ResponseData.toResponseEntity(ResponseCode.BAD_REQUEST_TOKEN);
+    }
+
     @ExceptionHandler(UserBadRequestException.class)
     public ResponseEntity handleUserBadRequestException(UserBadRequestException ex) {
         log.error(ex.getErrorStatus() + " " + ex.getErrorMessage() + "\n" + "==> error_messege / " + ex.getMessage());
diff --git a/src/main/java/com/sajang/devracebackend/response/ResponseCode.java b/src/main/java/com/sajang/devracebackend/response/ResponseCode.java
index 96af482..ae45344 100644
--- a/src/main/java/com/sajang/devracebackend/response/ResponseCode.java
+++ b/src/main/java/com/sajang/devracebackend/response/ResponseCode.java
@@ -80,6 +80,7 @@ public enum ResponseCode {
     // Token 실패 응답
     TOKEN_EXPIRED(StatusItem.UNAUTHORIZED, MessageItem.TOKEN_EXPIRED),
     TOKEN_ERROR(StatusItem.UNAUTHORIZED, MessageItem.TOKEN_ERROR),
+    BAD_REQUEST_TOKEN(StatusItem.BAD_REQUEST, MessageItem.BAD_REQUEST_TOKEN),
 
     // ===================== //
 
diff --git a/src/main/java/com/sajang/devracebackend/response/exception/exception400/TokenBadRequestException.java b/src/main/java/com/sajang/devracebackend/response/exception/exception400/TokenBadRequestException.java
new file mode 100644
index 0000000..7cc5759
--- /dev/null
+++ b/src/main/java/com/sajang/devracebackend/response/exception/exception400/TokenBadRequestException.java
@@ -0,0 +1,11 @@
+package com.sajang.devracebackend.response.exception.exception400;
+
+import com.sajang.devracebackend.response.exception.CustomException400;
+import com.sajang.devracebackend.response.responseitem.MessageItem;
+
+public class TokenBadRequestException extends CustomException400 {
+
+    public TokenBadRequestException(String message) {
+        super(MessageItem.BAD_REQUEST_TOKEN, message);
+    }
+}
diff --git a/src/main/java/com/sajang/devracebackend/response/responseitem/MessageItem.java b/src/main/java/com/sajang/devracebackend/response/responseitem/MessageItem.java
index c9b06e3..27a66b4 100644
--- a/src/main/java/com/sajang/devracebackend/response/responseitem/MessageItem.java
+++ b/src/main/java/com/sajang/devracebackend/response/responseitem/MessageItem.java
@@ -50,6 +50,7 @@ public class MessageItem {
 
     public static final String TOKEN_EXPIRED = "ERROR - JWT 토큰 만료 에러";
     public static final String TOKEN_ERROR = "ERROR - 잘못된 JWT 토큰 에러";
+    public static final String BAD_REQUEST_TOKEN = "ERROR - 잘못된 토큰 요청 에러";
 
     // < Etc >
     public static final String READ_DATA = "SUCCESS - 데이터 통합 조회 성공";  // 문제풀이 페이지 내 데이터들 조회 결과 응답시 사용할 예정.
diff --git a/src/main/java/com/sajang/devracebackend/security/jwt/TokenProvider.java b/src/main/java/com/sajang/devracebackend/security/jwt/TokenProvider.java
index 558b7cd..4dca323 100644
--- a/src/main/java/com/sajang/devracebackend/security/jwt/TokenProvider.java
+++ b/src/main/java/com/sajang/devracebackend/security/jwt/TokenProvider.java
@@ -99,7 +99,7 @@ public Authentication getAuthentication(String accessToken) {
         Claims claims = parseClaims(accessToken);  // Access Token의 Payload에 저장된 Claim을 꺼내옴. (JWT 토큰에서 사용자의 아이디와 권한 정보를 획득할 목적)
 
         if (claims.get(AUTHORITIES_KEY) == null) {
-            throw new RuntimeException("권한 정보가 없는 토큰입니다.");  // 500 Error가 적절함.
+            throw new RuntimeException("권한 정보가 없는 토큰입니다.");  // 클라이언트가 잘못된 요청을 한 것이 아니라, 서버에서 처리 중에 예기치 않은 에러가 발생한 것이기에, 403이 아닌 500 Error가 적절함.
         }
 
         // 해당 계정이 갖고있는 권한 목록들을 리턴하는 역할
diff --git a/src/main/java/com/sajang/devracebackend/service/TokenService.java b/src/main/java/com/sajang/devracebackend/service/TokenService.java
index ba6f6f4..87d2fbd 100644
--- a/src/main/java/com/sajang/devracebackend/service/TokenService.java
+++ b/src/main/java/com/sajang/devracebackend/service/TokenService.java
@@ -1,5 +1,9 @@
 package com.sajang.devracebackend.service;
 
+import com.sajang.devracebackend.dto.auth.ReissueRequestDto;
+import com.sajang.devracebackend.dto.auth.TokenDto;
+
 public interface TokenService {
+    TokenDto reissue(ReissueRequestDto reissueRequestDto);
     void updateRefreshToken(Long userId, String refreshToken);
 }
diff --git a/src/main/java/com/sajang/devracebackend/service/impl/TokenServiceImpl.java b/src/main/java/com/sajang/devracebackend/service/impl/TokenServiceImpl.java
index 7898c6e..c325fa6 100644
--- a/src/main/java/com/sajang/devracebackend/service/impl/TokenServiceImpl.java
+++ b/src/main/java/com/sajang/devracebackend/service/impl/TokenServiceImpl.java
@@ -1,9 +1,16 @@
 package com.sajang.devracebackend.service.impl;
 
 import com.sajang.devracebackend.domain.User;
+import com.sajang.devracebackend.domain.enums.Role;
+import com.sajang.devracebackend.dto.auth.ReissueRequestDto;
+import com.sajang.devracebackend.dto.auth.TokenDto;
+import com.sajang.devracebackend.response.exception.exception400.TokenBadRequestException;
+import com.sajang.devracebackend.security.jwt.TokenProvider;
 import com.sajang.devracebackend.service.TokenService;
 import com.sajang.devracebackend.service.UserService;
+import io.jsonwebtoken.JwtException;
 import lombok.RequiredArgsConstructor;
+import org.springframework.security.core.Authentication;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -12,8 +19,39 @@
 public class TokenServiceImpl implements TokenService {
 
     private final UserService userService;
+    private final TokenProvider tokenProvider;
 
 
+    @Transactional
+    @Override
+    public TokenDto reissue(ReissueRequestDto reissueRequestDto) {  // Refresh Token으로 Access Token 재발급 메소드
+
+        // RequestDto로 전달받은 Token값들
+        String accessToken = reissueRequestDto.getAccessToken();
+        String refreshToken = reissueRequestDto.getRefreshToken();
+
+        // Refresh Token 유효성 검사
+        if(tokenProvider.validateToken(refreshToken) == false) {
+            throw new JwtException("입력한 Refresh Token은 잘못된 토큰입니다.");
+        }
+
+        // Access Token에서 userId 가져오기
+        Authentication authentication = tokenProvider.getAuthentication(accessToken);
+        Long userId = Long.valueOf(authentication.getName());
+
+        // userId로 사용자 검색 & 해당 사용자의 role 가져오기
+        User user = userService.findUser(userId);
+        Role role = user.getRole();
+
+        // DB의 사용자 Refresh Token 값과, 전달받은 Refresh Token의 불일치 여부 검사
+        if(!user.getRefreshToken().equals(refreshToken)) {
+            throw new TokenBadRequestException("Refresh Token = " + refreshToken);
+        }
+
+        TokenDto tokenDto = tokenProvider.generateAccessTokenByRefreshToken(userId, role, refreshToken);
+        return tokenDto;
+    }
+
     @Transactional
     @Override
     public void updateRefreshToken(Long userId, String refreshToken) {