diff --git a/public/qr-code.html b/public/qr-code.html
index d38ef9f..67844e6 100644
--- a/public/qr-code.html
+++ b/public/qr-code.html
@@ -20,6 +20,6 @@
 {% block content %}
             <p class="text-small text-bold"><a href="/" class="text-no-decoration">← ホーム</a></p>
             <div class="big-image">
-                <img src="/assets/images/qr_code.svg" width="384" height="384">
+                <img src="/assets/images/qr_code.svg" width="256" height="256">
             </div>
 {% endblock %}