diff --git a/source/_layouts/website/header.html b/source/_layouts/website/header.html
index 92a528201..404a5a9e5 100644
--- a/source/_layouts/website/header.html
+++ b/source/_layouts/website/header.html
@@ -416,16 +416,6 @@ <h2 class="book-header-title-h" title="JavaScript Primer - 迷わないための
             setTimeout(() => console.clear(), 1000);
         });
     });
-    // unregister old service worker
-    navigator.serviceWorker.getRegistrations().then(function(registrations) {
-        for (const registration of registrations) {
-            registration.unregister();
-        }
-    }).catch(function(err) {
-        console.error(new Error("Can not getRegistrations", {
-            cause: err
-        }));
-    });
 </script>
 {% endblock %}
 
diff --git a/source/_layouts/website/page.html b/source/_layouts/website/page.html
index 39d91edea..cfbb9f2ed 100644
--- a/source/_layouts/website/page.html
+++ b/source/_layouts/website/page.html
@@ -165,23 +165,17 @@
 <meta name="theme-color" content="#ffffff">
 <link rel="manifest" href="{{ "/manifest.json"|resolveFile }}">
 <script>
-    if ("serviceWorker" in navigator) {
-        const isLocalhost = Boolean(
-            // preview
-            /netlify.com/.test(window.location.hostname) ||
-            // local
-            window.location.hostname === "localhost" ||
-            // [::1] is the IPv6 localhost address.
-            window.location.hostname === "[::1]" ||
-            // 127.0.0.1/8 is considered localhost for IPv4.
-            window.location.hostname.match(/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/)
-        );
-        if (!isLocalhost) {
-            window.addEventListener("load", () => {
-                navigator.serviceWorker.register("{{ '/sw.js'|resolveFile }}");
-            });
+    // unregister old service worker(remove workbox)
+    // https://github.com/asciidwango/js-primer/pull/1701
+    navigator.serviceWorker.getRegistrations().then(function(registrations) {
+        for (const registration of registrations) {
+            registration.unregister();
         }
-    }
+    }).catch(function(err) {
+        console.error(new Error("Can not getRegistrations", {
+            cause: err
+        }));
+    });
 </script>
 {% endblock %}
 {% block book_inner %} {{ super() }}