diff --git a/frontend/src/components/EpisodeDetail.tsx b/frontend/src/components/EpisodeDetail.tsx
index abd46ac..1499355 100644
--- a/frontend/src/components/EpisodeDetail.tsx
+++ b/frontend/src/components/EpisodeDetail.tsx
@@ -17,6 +17,8 @@ interface EpisodeWithFeedInfo {
   feedId: string;
   feedTitle?: string;
   feedUrl: string;
+  category?: string;
+  feedCategory?: string;
 }
 
 function EpisodeDetail() {
diff --git a/frontend/src/components/EpisodeList.tsx b/frontend/src/components/EpisodeList.tsx
index 911a672..2938c0d 100644
--- a/frontend/src/components/EpisodeList.tsx
+++ b/frontend/src/components/EpisodeList.tsx
@@ -164,20 +164,14 @@ function EpisodeList() {
     }
   };
 
-  const filterEpisodesByCategory = async () => {
+  const filterFeedsByCategory = () => {
     if (!selectedCategory) {
       setFilteredEpisodes(episodes);
     } else {
-      const response = await fetch(
-        `/api/episodes/by-category?category=${selectedCategory}`,
+      const filtered = episodes.filter(
+        (ep) => ep.category === selectedCategory,
       );
-      if (!response.ok) {
-        setError("カテゴリの取得に失敗しました");
-        return;
-      }
-      const episodes = await response.json();
-
-      setFilteredEpisodes(episodes);
+      setFilteredEpisodes(filtered);
     }
   };