diff --git a/src/functions/post/_middleware.tsx b/functions/post/_middleware.tsx
similarity index 100%
rename from src/functions/post/_middleware.tsx
rename to functions/post/_middleware.tsx
diff --git a/src/pages/404.astro b/src/pages/404.astro
new file mode 100644
index 0000000..248188e
--- /dev/null
+++ b/src/pages/404.astro
@@ -0,0 +1,8 @@
+---
+import Layout from "../layouts/Layout.astro";
+---
+
+<Layout title="404 Not Found" description="ページが見つかりませんでした。">
+  <h1 class="text-4xl">404 Not Found</h1>
+  <p>ページが見つかりませんでした。</p>
+</Layout>