diff --git a/YDS-Storybook/CaseTestViewController/View/TextFieldCaseTestBaseViewController.swift b/YDS-Storybook/CaseTestViewController/View/TextFieldCaseTestBaseViewController.swift
index a117669d..35baedc6 100644
--- a/YDS-Storybook/CaseTestViewController/View/TextFieldCaseTestBaseViewController.swift
+++ b/YDS-Storybook/CaseTestViewController/View/TextFieldCaseTestBaseViewController.swift
@@ -128,10 +128,10 @@ class TextFieldCaseTestBaseViewController: UIViewController {
             })
             .disposed(by: bag)
         
-        viewModel.shouldShowToastMessage
+        viewModel.shouldPresentAlert
             .filter { $0 }
-            .subscribe(onNext: { _ in
-                YDSToast.makeToast(text: "중복 닉네임입니다.", duration: .short)
+            .subscribe(onNext: { [weak self] _ in
+                self?.showAlert(title: nil, message: "중복 닉네임입니다.")
             })
             .disposed(by: bag)
         
@@ -162,3 +162,14 @@ extension TextFieldCaseTestBaseViewController {
         self.view.endEditing(true)
     }
 }
+
+//  MARK: - Alert
+extension TextFieldCaseTestBaseViewController {
+    private func showAlert(title: String?, message: String?) {
+        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
+        let action = UIAlertAction(title: "확인", style: .default, handler: nil)
+        alert.addAction(action)
+        alert.view.tintColor = YDSColor.buttonPoint
+        present(alert, animated: true, completion: nil)
+    }
+}
diff --git a/YDS-Storybook/CaseTestViewController/ViewModel/TextFieldCaseTestViewModel.swift b/YDS-Storybook/CaseTestViewController/ViewModel/TextFieldCaseTestViewModel.swift
index 108e598a..8c55a850 100644
--- a/YDS-Storybook/CaseTestViewController/ViewModel/TextFieldCaseTestViewModel.swift
+++ b/YDS-Storybook/CaseTestViewController/ViewModel/TextFieldCaseTestViewModel.swift
@@ -26,7 +26,7 @@ class TextFieldCaseTestViewModel {
     func confirmButtonDidTap() {
         textFieldIsNegative.onNext(true)
         confirmButtonIsDisabled.onNext(true)
-        shouldShowToastMessage.onNext(true)
+        shouldPresentAlert.onNext(true)
         
         switch caseType {
         case .withHaptic:
@@ -48,7 +48,7 @@ class TextFieldCaseTestViewModel {
     let textFieldIsNegative = BehaviorSubject<Bool>(value: false)
     let textFieldShoudShake = PublishSubject<Bool>()
     let textFieldShoudShakeWithHaptic = PublishSubject<Bool>()
-    let shouldShowToastMessage = PublishSubject<Bool>()
+    let shouldPresentAlert = PublishSubject<Bool>()
     
     //  MARK: - Private Observable
     private let text = PublishSubject<String?>()