diff --git a/src/main/java/dbdr/domain/careworker/controller/CareworkerController.java b/src/main/java/dbdr/domain/careworker/controller/CareworkerController.java
index ddd50334..dce107be 100644
--- a/src/main/java/dbdr/domain/careworker/controller/CareworkerController.java
+++ b/src/main/java/dbdr/domain/careworker/controller/CareworkerController.java
@@ -8,7 +8,6 @@
 
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.http.ResponseEntity;
-import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.web.bind.annotation.*;
 
 import java.net.URI;
@@ -17,7 +16,6 @@
 @RestController
 @RequestMapping("/${spring.app.version}/careworker")
 @RequiredArgsConstructor
-@PreAuthorize("hasAnyAuthority('ADMIN')")
 public class CareworkerController {
 
     private final CareworkerService careworkerService;
diff --git a/src/main/java/dbdr/domain/careworker/repository/CareworkerRepository.java b/src/main/java/dbdr/domain/careworker/repository/CareworkerRepository.java
index b5593615..714c2b4d 100644
--- a/src/main/java/dbdr/domain/careworker/repository/CareworkerRepository.java
+++ b/src/main/java/dbdr/domain/careworker/repository/CareworkerRepository.java
@@ -11,12 +11,13 @@ public interface CareworkerRepository extends JpaRepository<Careworker, Long> {
 
     List<Careworker> findByInstitutionId(Long institutionId);
 
-    boolean existsByEmail(String email);
-
     Optional<Careworker> findByLineUserId(String userId);
 
     List<Careworker> findByAlertTime(LocalTime currentTime);
 
 	Optional<Careworker> findByPhone(String phoneNumber);
-    boolean existsByPhone(String phone);
+
+    boolean ensureUniqueEmail(String email);
+
+    boolean ensureUniquePhone(String phone);
 }
diff --git a/src/main/java/dbdr/domain/careworker/service/CareworkerService.java b/src/main/java/dbdr/domain/careworker/service/CareworkerService.java
index 6b439be4..625143ce 100644
--- a/src/main/java/dbdr/domain/careworker/service/CareworkerService.java
+++ b/src/main/java/dbdr/domain/careworker/service/CareworkerService.java
@@ -78,7 +78,7 @@ private Careworker findCareworkerById(Long id) {
     }
 
     private void emailExists(String email) {
-        if (careworkerRepository.existsByEmail(email)) {
+        if (careworkerRepository.ensureUniqueEmail(email)) {
             throw new ApplicationException(ApplicationError.DUPLICATE_EMAIL);
         }
     }
diff --git a/src/main/java/dbdr/domain/excel/service/ExcelUploadService.java b/src/main/java/dbdr/domain/excel/service/ExcelUploadService.java
index 75b6c307..1b8a5048 100644
--- a/src/main/java/dbdr/domain/excel/service/ExcelUploadService.java
+++ b/src/main/java/dbdr/domain/excel/service/ExcelUploadService.java
@@ -82,7 +82,7 @@ private void processCareworkerRow(Row row, List<FileDataResponseDto> successList
 
         try {
             checkDuplicate(seenPhones, phone, ApplicationError.DUPLICATE_PHONE);
-            validatePhone(phone, careworkerRepository.existsByPhone(phone));
+            validatePhone(phone, careworkerRepository.ensureUniquePhone(phone));
             seenPhones.add(phone);
 
             Careworker careworker = Careworker.builder()
@@ -104,7 +104,7 @@ private void processGuardianRow(Row row, List<FileDataResponseDto> successList,
 
         try {
             checkDuplicate(seenPhones, phone, ApplicationError.DUPLICATE_PHONE);
-            validatePhone(phone, guardianRepository.existsByPhone(phone));
+            validatePhone(phone, guardianRepository.ensureUniquePhone(phone));
             seenPhones.add(phone);
 
             Guardian guardian = Guardian.builder()
@@ -127,7 +127,7 @@ private void processRecipientRow(Row row, List<FileDataResponseDto> successList,
 
         try {
             checkDuplicate(seenCareNumbers, careNumber, ApplicationError.DUPLICATE_CARE_NUMBER);
-            validateCareNumber(careNumber, recipientRepository.existsByCareNumber(careNumber));
+            validateCareNumber(careNumber, recipientRepository.ensureUniqueCareNumber(careNumber));
             seenCareNumbers.add(careNumber);
 
             Recipient recipient = Recipient.builder()
diff --git a/src/main/java/dbdr/domain/guardian/repository/GuardianRepository.java b/src/main/java/dbdr/domain/guardian/repository/GuardianRepository.java
index ecf00897..04985abf 100644
--- a/src/main/java/dbdr/domain/guardian/repository/GuardianRepository.java
+++ b/src/main/java/dbdr/domain/guardian/repository/GuardianRepository.java
@@ -10,7 +10,7 @@
 
 public interface GuardianRepository extends JpaRepository<Guardian, Long> {
 
-    boolean existsByPhone(String phone);
+    boolean ensureUniquePhone(String phone);
 
     Optional<Guardian> findByLineUserId(String userId);
 
diff --git a/src/main/java/dbdr/domain/guardian/service/GuardianService.java b/src/main/java/dbdr/domain/guardian/service/GuardianService.java
index df0b2bda..cf61c5c0 100644
--- a/src/main/java/dbdr/domain/guardian/service/GuardianService.java
+++ b/src/main/java/dbdr/domain/guardian/service/GuardianService.java
@@ -60,7 +60,7 @@ private Guardian findGuardianById(Long guardianId) {
     }
 
     private void phoneNumberExists(String phone) {
-        if (guardianRepository.existsByPhone(phone)) {
+        if (guardianRepository.ensureUniquePhone(phone)) {
             throw new ApplicationException(ApplicationError.DUPLICATE_PHONE);
         }
     }
diff --git a/src/main/java/dbdr/domain/institution/repository/InstitutionRepository.java b/src/main/java/dbdr/domain/institution/repository/InstitutionRepository.java
index 677c77e1..fd578597 100644
--- a/src/main/java/dbdr/domain/institution/repository/InstitutionRepository.java
+++ b/src/main/java/dbdr/domain/institution/repository/InstitutionRepository.java
@@ -5,7 +5,7 @@
 
 public interface InstitutionRepository extends JpaRepository<Institution, Long> {
 
-    boolean existsByInstitutionNumber(Long institutionNumber);
+    boolean ensureUniqueInstitutionNumber(Long institutionNumber);
 
     Institution findByInstitutionNumber(Long institutionNumber);
 }
diff --git a/src/main/java/dbdr/domain/institution/service/InstitutionService.java b/src/main/java/dbdr/domain/institution/service/InstitutionService.java
index 40e6dfed..c4a304d7 100644
--- a/src/main/java/dbdr/domain/institution/service/InstitutionService.java
+++ b/src/main/java/dbdr/domain/institution/service/InstitutionService.java
@@ -56,7 +56,7 @@ public void deleteInstitutionById(Long id) {
     }
 
     private void institutionIdExists(Long institutionNumber) {
-        if (institutionRepository.existsByInstitutionNumber(institutionNumber)) {
+        if (institutionRepository.ensureUniqueInstitutionNumber(institutionNumber)) {
             throw new ApplicationException(ApplicationError.DUPLICATE_INSTITUTION_NUMBER);
         }
     }
diff --git a/src/main/java/dbdr/domain/recipient/repository/RecipientRepository.java b/src/main/java/dbdr/domain/recipient/repository/RecipientRepository.java
index e056c3e5..3bdd9add 100644
--- a/src/main/java/dbdr/domain/recipient/repository/RecipientRepository.java
+++ b/src/main/java/dbdr/domain/recipient/repository/RecipientRepository.java
@@ -5,5 +5,5 @@
 
 public interface RecipientRepository extends JpaRepository<Recipient, Long> {
 
-    boolean existsByCareNumber(String careNumber);
+    boolean ensureUniqueCareNumber(String careNumber);
 }
diff --git a/src/main/java/dbdr/domain/recipient/service/RecipientService.java b/src/main/java/dbdr/domain/recipient/service/RecipientService.java
index 0bbeace2..d83669ab 100644
--- a/src/main/java/dbdr/domain/recipient/service/RecipientService.java
+++ b/src/main/java/dbdr/domain/recipient/service/RecipientService.java
@@ -79,7 +79,7 @@ private Recipient findRecipientById(Long id) {
     }
 
     private void careNumberExists(String careNumber) {
-        if (recipientRepository.existsByCareNumber(careNumber)) {
+        if (recipientRepository.ensureUniqueCareNumber(careNumber)) {
             throw new ApplicationException(ApplicationError.DUPLICATE_CARE_NUMBER);
         }
     }
diff --git a/src/main/java/dbdr/security/service/BaseUserDetailsService.java b/src/main/java/dbdr/security/service/BaseUserDetailsService.java
index 1d8b730c..a717cb55 100644
--- a/src/main/java/dbdr/security/service/BaseUserDetailsService.java
+++ b/src/main/java/dbdr/security/service/BaseUserDetailsService.java
@@ -45,7 +45,7 @@ public BaseUserDetails loadUserByUsernameAndRole(String username, Role role) {
     }
 
     private BaseUserDetails getInstitutionDetails(String userId) {
-        if (!institutionRepository.existsByInstitutionNumber(Long.parseLong(userId))) {
+        if (!institutionRepository.ensureUniqueInstitutionNumber(Long.parseLong(userId))) {
             throw new ApplicationException(ApplicationError.INSTITUTION_NOT_FOUND);
         }