diff --git a/src/main/java/com/nice/petudio/api/controller/auth/AuthController.java b/src/main/java/com/nice/petudio/api/controller/auth/AuthController.java
index c674f50..48fcb30 100644
--- a/src/main/java/com/nice/petudio/api/controller/auth/AuthController.java
+++ b/src/main/java/com/nice/petudio/api/controller/auth/AuthController.java
@@ -1,6 +1,7 @@
 package com.nice.petudio.api.controller.auth;
 
 import com.nice.petudio.api.controller.auth.dto.request.LoginRequest;
+import com.nice.petudio.api.controller.auth.dto.request.ReissueRequest;
 import com.nice.petudio.api.controller.auth.dto.request.SignUpRequest;
 import com.nice.petudio.api.controller.auth.vo.TokenVO;
 import com.nice.petudio.api.controller.auth.service.AuthService;
@@ -71,10 +72,8 @@ public ApiResponse<String> logout(@MemberId final Long memberId) {
     @Operation(summary = "JWT 토큰 갱신")
     @ResponseStatus(HttpStatus.OK)
     @PostMapping("/auth/reissue")
-    public ApiResponse<?> reissue(@CookieValue final String accessToken, @CookieValue final String refreshToken,
-                                  HttpServletResponse response) {
-        TokenVO tokenVO = TokenVO.of(accessToken, refreshToken);
-        addTokensToCookie(createTokenService.reissueToken(tokenVO), response);
+    public ApiResponse<?> reissue(ReissueRequest request, HttpServletResponse response) {
+        addTokensToCookie(createTokenService.reissueToken(request), response);
 
         return ApiResponse.success();
     }
diff --git a/src/main/java/com/nice/petudio/api/controller/auth/dto/request/ReissueRequest.java b/src/main/java/com/nice/petudio/api/controller/auth/dto/request/ReissueRequest.java
new file mode 100644
index 0000000..0b70f27
--- /dev/null
+++ b/src/main/java/com/nice/petudio/api/controller/auth/dto/request/ReissueRequest.java
@@ -0,0 +1,4 @@
+package com.nice.petudio.api.controller.auth.dto.request;
+
+public record ReissueRequest(String accessToken, String refreshToken) {
+}
diff --git a/src/main/java/com/nice/petudio/api/controller/auth/service/CreateTokenService.java b/src/main/java/com/nice/petudio/api/controller/auth/service/CreateTokenService.java
index 8bfa191..30c3fe7 100644
--- a/src/main/java/com/nice/petudio/api/controller/auth/service/CreateTokenService.java
+++ b/src/main/java/com/nice/petudio/api/controller/auth/service/CreateTokenService.java
@@ -1,14 +1,15 @@
 package com.nice.petudio.api.controller.auth.service;
 
 
+import com.nice.petudio.api.controller.auth.dto.request.ReissueRequest;
 import com.nice.petudio.api.controller.auth.vo.TokenVO;
 import com.nice.petudio.api.controller.member.service.MemberServiceUtils;
-import com.nice.petudio.domain.member.Member;
-import com.nice.petudio.domain.member.repository.MemberRepository;
 import com.nice.petudio.common.auth.jwt.JwtUtils;
 import com.nice.petudio.common.config.redis.constant.RedisKey;
-import com.nice.petudio.common.exception.model.UnAuthorizedException;
 import com.nice.petudio.common.exception.error.ErrorCode;
+import com.nice.petudio.common.exception.model.UnAuthorizedException;
+import com.nice.petudio.domain.member.Member;
+import com.nice.petudio.domain.member.repository.MemberRepository;
 import java.util.List;
 import java.util.Objects;
 import lombok.RequiredArgsConstructor;
@@ -32,21 +33,22 @@ public TokenVO createTokenInfo(Long memberId) {
         return TokenVO.of(tokens.get(0), tokens.get(1));
     }
 
-    public TokenVO reissueToken(final TokenVO tokenVO) {
-        Long memberId = jwtUtils.parseMemberId(tokenVO.getAccessToken())
+    public TokenVO reissueToken(final ReissueRequest request) {
+        Long memberId = jwtUtils.parseMemberId(request.accessToken())
                 .orElseThrow();
         Member member = MemberServiceUtils.findMemberById(memberRepository, memberId);
 
-        if (!jwtUtils.validateToken(tokenVO.getRefreshToken())) {
+        if (!jwtUtils.validateToken(request.refreshToken())) {
             throw new UnAuthorizedException(ErrorCode.UNAUTHORIZED_JWT_EXCEPTION,
-                    String.format("MemberId(%d)의 토큰 갱신 요청에 포함된 Refresh Token이 유효하지 않아, Token Refresh가 수행되지 않았습니다.", memberId));
+                    String.format("MemberId(%d)의 토큰 갱신 요청에 포함된 Refresh Token이 유효하지 않아, Token Refresh가 수행되지 않았습니다.",
+                            memberId));
         }
         String refreshToken = (String) redisTemplate.opsForValue().get(RedisKey.REFRESH_TOKEN + memberId.toString());
         if (Objects.isNull(refreshToken)) {
             throw new UnAuthorizedException(ErrorCode.UNAUTHORIZED_JWT_EXCEPTION,
                     String.format("보관 중인 MemberId(%d)의 Refresh Token이 존재하지 않아, Token Refresh가 수행되지 않았습니다.", memberId));
         }
-        if (!refreshToken.equals(tokenVO.getRefreshToken())) {
+        if (!refreshToken.equals(request.refreshToken())) {
             jwtUtils.expireRefreshToken(member.getId());
             throw new UnAuthorizedException(ErrorCode.UNAUTHORIZED_JWT_EXCEPTION,
                     String.format("보관 중인 MemberId(%d)의 Refresh Token이 유효하지 않아, Token Refresh가 수행되지 않았습니다.", memberId));
diff --git a/src/main/java/com/nice/petudio/common/aop/advice/ExceptionControllerAdvice.java b/src/main/java/com/nice/petudio/common/aop/advice/ExceptionControllerAdvice.java
index 09e3f16..fe80d6a 100644
--- a/src/main/java/com/nice/petudio/common/aop/advice/ExceptionControllerAdvice.java
+++ b/src/main/java/com/nice/petudio/common/aop/advice/ExceptionControllerAdvice.java
@@ -4,6 +4,7 @@
 import com.nice.petudio.api.dto.ApiResponse;
 import com.nice.petudio.common.exception.error.ErrorCode;
 import com.nice.petudio.common.exception.model.BadGatewayException;
+import com.nice.petudio.common.exception.model.ConflictException;
 import com.nice.petudio.common.exception.model.InternalServerException;
 import com.nice.petudio.common.exception.model.ValidationException;
 import lombok.extern.slf4j.Slf4j;
@@ -30,6 +31,14 @@ protected ApiResponse<Object> handleValidateException(ValidationException except
         return ApiResponse.error(exception.getErrorCode());
     }
 
+    // 중복되는 데이터 저장 요청의 경우(e.g. 같은 같은 계정으로 OAuth2 회원가입 시도) 발생
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    @ExceptionHandler(ConflictException.class)
+    protected ApiResponse<Object> handleConflictException(ConflictException exception) {
+        log.error(exception.getMessage(), exception);
+        return ApiResponse.error(exception.getErrorCode());
+    }
+
     // @Valid or @Validated 바인딩 에러시 발생
     @ResponseStatus(HttpStatus.BAD_REQUEST)
     @ExceptionHandler(MethodArgumentNotValidException.class)
diff --git a/src/main/java/com/nice/petudio/common/auth/handler/AuthCheckHandler.java b/src/main/java/com/nice/petudio/common/auth/handler/AuthCheckHandler.java
index 4095d86..12461a1 100644
--- a/src/main/java/com/nice/petudio/common/auth/handler/AuthCheckHandler.java
+++ b/src/main/java/com/nice/petudio/common/auth/handler/AuthCheckHandler.java
@@ -1,21 +1,20 @@
 package com.nice.petudio.common.auth.handler;
 
 import com.nice.petudio.api.controller.member.service.MemberServiceUtils;
-import com.nice.petudio.domain.member.Member;
-import com.nice.petudio.domain.member.MemberRole;
-import com.nice.petudio.domain.member.repository.MemberRepository;
 import com.nice.petudio.common.auth.jwt.JwtUtils;
+import com.nice.petudio.common.exception.error.ErrorCode;
 import com.nice.petudio.common.exception.model.ForbiddenException;
 import com.nice.petudio.common.exception.model.UnAuthorizedException;
 import com.nice.petudio.common.exception.model.ValidationException;
-import com.nice.petudio.common.exception.error.ErrorCode;
-import jakarta.servlet.http.Cookie;
+import com.nice.petudio.domain.member.Member;
+import com.nice.petudio.domain.member.MemberRole;
+import com.nice.petudio.domain.member.repository.MemberRepository;
 import jakarta.servlet.http.HttpServletRequest;
-import java.util.Arrays;
 import java.util.List;
 import java.util.Optional;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Component;
+import org.springframework.util.StringUtils;
 
 @RequiredArgsConstructor
 @Component
@@ -25,7 +24,6 @@ public class AuthCheckHandler {
     private final MemberRepository memberRepository;
     private Long memberId;
 
-    private static final String JWT_ACCESS_TOKEN_COOKIE_NAME = "accessToken";
 
     public Long validateAuthority(HttpServletRequest request, List<MemberRole> requiredRoles) {
         String jwtAccessToken = getJwtAccessTokenFromHttpCookie(request);
@@ -37,20 +35,14 @@ public Long validateAuthority(HttpServletRequest request, List<MemberRole> requi
     }
 
     private String getJwtAccessTokenFromHttpCookie(HttpServletRequest request) {
-        Optional<Cookie> jwtAccessTokenCookie = getJwtAccessTokenCookieFromHttpRequest(request);
-        if (jwtAccessTokenCookie.isPresent()) {
-            return jwtAccessTokenCookie.get().getValue();
+        String bearerToken = request.getHeader("Authorization");
+        if (StringUtils.hasText(bearerToken) && bearerToken.startsWith("Bearer ")) {
+            return bearerToken.substring("Bearer ".length());
         }
         throw new ValidationException(ErrorCode.INVALID_JWT_TOKEN_EXCEPTION,
                 ErrorCode.INVALID_JWT_TOKEN_EXCEPTION.getMessage());
     }
 
-    private Optional<Cookie> getJwtAccessTokenCookieFromHttpRequest(HttpServletRequest request) {
-        return Arrays.stream(request.getCookies())
-                .filter(cookie -> cookie.getName().equals(JWT_ACCESS_TOKEN_COOKIE_NAME))
-                .findFirst();
-    }
-
     public boolean hasAuthority(String jwtAccessToken, List<MemberRole> requiredRoles) {
         if (jwtUtils.validateToken(jwtAccessToken)) {
             Optional<Long> memberId = jwtUtils.parseMemberId(jwtAccessToken);