diff --git a/extension/script/add-search-index.js b/extension/script/add-search-index.js
index 2f432e99..10f6c087 100644
--- a/extension/script/add-search-index.js
+++ b/extension/script/add-search-index.js
@@ -69,15 +69,22 @@
         }
 
         if (searchIndexJs) {
-            let script = document.createElement('script');
-            script.src = searchIndexJs;
-            script.onload = sendSearchIndex;
-            document.head.append(script);
+            if (location.pathname.startsWith("/nightly/nightly-rustc/")) {
+                loadSearchIndex("/nightly/nightly-rustc/search-index.js");
+            } else {
+                loadSearchIndex(searchIndexJs);
+            }
         } else {
             console.error("Sorry, no search index found.");
         }
     }
 
+    function loadSearchIndex(searchIndexJs) {
+        let script = document.createElement('script');
+        script.src = searchIndexJs;
+        script.onload = sendSearchIndex;
+        document.head.append(script);
+    }
 
     // [rustdoc] Use Map instead of Object for source files and search index #118910
     // https://github.com/rust-lang/rust/pull/118910