diff --git a/src/main/java/com/eactive/apim/portal/apps/user/service/PortalUserAuthService.java b/src/main/java/com/eactive/apim/portal/apps/user/service/PortalUserAuthService.java
index f79a34f..ec03752 100644
--- a/src/main/java/com/eactive/apim/portal/apps/user/service/PortalUserAuthService.java
+++ b/src/main/java/com/eactive/apim/portal/apps/user/service/PortalUserAuthService.java
@@ -75,9 +75,10 @@ public class PortalUserAuthService implements UserDetailsService {
 
     public List<PortalUserDTO> findAllUsersByNameAndMobile(String userName, String mobileNumber) {
         try {
-            // 전화번호에서 - 제거하여 조회
-            String normalizedMobileNumber = mobileNumber != null ? mobileNumber.replace("-", "") : null;
-            List<PortalUser> users = portalUserRepository.findAllByUserNameAndMobileNumber(userName, normalizedMobileNumber);
+            if (mobileNumber == null || !mobileNumber.matches("^\\d{2,3}-\\d{3,4}-\\d{4}$")) {
+                throw new UserNotFoundException("유효하지 않은 휴대폰 번호 형식입니다.");
+            }
+            List<PortalUser> users = portalUserRepository.findAllByUserNameAndMobileNumber(userName, mobileNumber);
             if (users == null || users.isEmpty()) {
                 throw new UserNotFoundException("입력하신 사용자 정보가 올바르지 않습니다. 다시 확인해 주세요.");
             }