diff --git a/app/layout.tsx b/app/layout.tsx
index ae381a0..284ab94 100644
--- a/app/layout.tsx
+++ b/app/layout.tsx
@@ -1,8 +1,8 @@
 import type { Metadata } from "next";
 import { Geist, Geist_Mono, Inter } from "next/font/google";
-import Link from "next/link";
 import "./globals.css";
 import { cn } from "@/lib/utils";
+import { SiteHeader } from "@/components/site-header";
 
 const inter = Inter({subsets:['latin'],variable:'--font-sans'});
 
@@ -32,21 +32,7 @@ export default function RootLayout({
       className={cn("h-full", "antialiased", geistSans.variable, geistMono.variable, "font-sans", inter.variable)}
     >
       <body className="min-h-full flex flex-col">
-        <header className="sticky top-0 z-40 border-b bg-background/85 backdrop-blur motion-safe:animate-in motion-safe:fade-in motion-safe:slide-in-from-top-2 motion-safe:duration-500">
-          <div className="mx-auto flex w-full max-w-6xl items-center justify-between px-4 py-3 sm:px-8">
-            <Link href="/" className="text-sm font-semibold tracking-tight transition-colors duration-200 hover:text-primary sm:text-base">
-              Takasumi-Neodyマイクラサーバプロジェクト
-            </Link>
-            <nav className="flex items-center gap-4 text-sm">
-              <Link href="/" className="underline-offset-4 transition-colors duration-200 hover:text-primary hover:underline">
-                メインページ
-              </Link>
-              <Link href="/announcements" className="underline-offset-4 transition-colors duration-200 hover:text-primary hover:underline">
-                お知らせ
-              </Link>
-            </nav>
-          </div>
-        </header>
+        <SiteHeader />
         {children}
       </body>
     </html>
diff --git a/components/site-header.tsx b/components/site-header.tsx
new file mode 100644
index 0000000..9611f81
--- /dev/null
+++ b/components/site-header.tsx
@@ -0,0 +1,30 @@
+import Link from "next/link";
+
+export function SiteHeader() {
+  return (
+    <header className="sticky top-0 z-40 border-b bg-background/85 backdrop-blur motion-safe:animate-in motion-safe:fade-in motion-safe:slide-in-from-top-2 motion-safe:duration-500">
+      <div className="mx-auto flex w-full max-w-6xl items-center justify-between px-4 py-3 sm:px-8">
+        <Link
+          href="/"
+          className="text-sm font-semibold tracking-tight transition-colors duration-200 hover:text-primary sm:text-base"
+        >
+          Takasumi-Neodyマイクラサーバプロジェクト
+        </Link>
+        <nav className="flex items-center gap-4 text-sm">
+          <Link
+            href="/"
+            className="underline-offset-4 transition-colors duration-200 hover:text-primary hover:underline"
+          >
+            メインページ
+          </Link>
+          <Link
+            href="/announcements"
+            className="underline-offset-4 transition-colors duration-200 hover:text-primary hover:underline"
+          >
+            お知らせ
+          </Link>
+        </nav>
+      </div>
+    </header>
+  );
+}
