diff --git a/packages/ui/src/Dialog/Dialog.tsx b/packages/ui/src/Dialog/Dialog.tsx
index 242b05af..5b759724 100644
--- a/packages/ui/src/Dialog/Dialog.tsx
+++ b/packages/ui/src/Dialog/Dialog.tsx
@@ -4,7 +4,7 @@ import { Dialog as HeadlessDialog, Transition } from '@headlessui/react';
 
 type Props = Readonly<{
   children: React.ReactNode;
-  isShown?: boolean;
+  isShown: boolean;
   onClose: () => void;
   primaryButton: React.ReactNode;
   secondaryButton?: React.ReactNode;