diff --git a/kyokusui/controller.py b/kyokusui/controller.py
index 178d25e..56aee65 100644
--- a/kyokusui/controller.py
+++ b/kyokusui/controller.py
@@ -139,7 +139,8 @@ def retrieve(self, request):
         return Response.render(template, {
             "board": board,
             "thread": thread,
-            "boards": Board.list_subscribed(request.user)
+            "boards": Board.list_subscribed(request.user),
+            "ws_scheme": "ws" if request.scheme == "http" else "wss"
         })
 
     def log(self, request):
diff --git a/kyokusui/templates/thread.html b/kyokusui/templates/thread.html
index 2fd7906..f424fc0 100644
--- a/kyokusui/templates/thread.html
+++ b/kyokusui/templates/thread.html
@@ -89,7 +89,7 @@ <h5 class='modal-title'>スレッドを締めますか？</h5>
 const textarea = document.querySelector("#message")
 const image_form = document.querySelector("#image")
 const image2send = document.querySelector("#image2send")
-const ws = new WebSocket("{{ fullurl(request, "/api/v0/board/" + board._id + "/" + thread._id + "/socket", scheme="ws" if request.scheme == "http" else "wss") }}")
+const ws = new WebSocket("{{ fullurl(request, "/api/v0/board/" + board._id + "/" + thread._id + "/socket", scheme=ws_scheme) }}")
 image_form.onchange = async e => {
     const files = await Promise.all(Array.from(e.target.files).map(f => {
         return new Promise((resolve, reject) => {