diff --git a/app/root.tsx b/app/root.tsx
index ce60279..85102e4 100644
--- a/app/root.tsx
+++ b/app/root.tsx
@@ -65,7 +65,10 @@ export const meta: Route.MetaFunction = () => [
 ];
 
 export const links: Route.LinksFunction = () => [
-  { rel: "icon", href: "/logo.png", type: "image/png" },
+  // Google検索のファビコンは正方形(48pxの倍数推奨)が必須なので、横長の logo.png ではなく正方形版を使う
+  { rel: "icon", href: "/favicon.ico", sizes: "16x16 32x32 48x48" },
+  { rel: "icon", href: "/favicon-192.png", type: "image/png", sizes: "192x192" },
+  { rel: "apple-touch-icon", href: "/apple-touch-icon.png" },
   { rel: "preconnect", href: "https://fonts.googleapis.com" },
   { rel: "preconnect", href: "https://fonts.gstatic.com", crossOrigin: "anonymous" },
   {
diff --git a/public/apple-touch-icon.png b/public/apple-touch-icon.png
new file mode 100644
index 0000000..18beeba
Binary files /dev/null and b/public/apple-touch-icon.png differ
diff --git a/public/favicon-192.png b/public/favicon-192.png
new file mode 100644
index 0000000..8eb0d32
Binary files /dev/null and b/public/favicon-192.png differ
diff --git a/public/favicon.ico b/public/favicon.ico
new file mode 100644
index 0000000..f410a07
Binary files /dev/null and b/public/favicon.ico differ