diff --git a/CHANGELOG.md b/CHANGELOG.md
index fd56700e1f..8119bdaf57 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@
 - Fix: 絵文字管理画面で一部の絵文字が表示されない問題を修正
 
 ### Server
+- Fix: URLをデコードしてからリクエストを送信するように
 - Fix: ユーザーのプロフィール画面をアドレス入力などで直接表示した際に概要タブの描画に失敗する問題の修正( #15032 )
 - Fix: 起動前の疎通チェックが機能しなくなっていた問題を修正  
   (Cherry-picked from https://activitypub.software/TransFem-org/Sharkey/-/merge_requests/737)
diff --git a/packages/backend/src/core/HttpRequestService.ts b/packages/backend/src/core/HttpRequestService.ts
index 083153940a..7e52b80cb0 100644
--- a/packages/backend/src/core/HttpRequestService.ts
+++ b/packages/backend/src/core/HttpRequestService.ts
@@ -283,6 +283,7 @@ export class HttpRequestService {
 		},
 	): Promise<Response> {
 		const timeout = args.timeout ?? 5000;
+		const decodedUrl = decodeURIComponent(url);
 
 		const controller = new AbortController();
 		setTimeout(() => {
@@ -291,7 +292,7 @@ export class HttpRequestService {
 
 		const isLocalAddressAllowed = args.isLocalAddressAllowed ?? false;
 
-		const res = await fetch(url, {
+		const res = await fetch(decodedUrl, {
 			method: args.method ?? 'GET',
 			headers: {
 				'User-Agent': this.config.userAgent,
@@ -299,7 +300,7 @@ export class HttpRequestService {
 			},
 			body: args.body,
 			size: args.size ?? 10 * 1024 * 1024,
-			agent: (url) => this.getAgentByUrl(url, false, isLocalAddressAllowed),
+			agent: (decodedUrl) => this.getAgentByUrl(decodedUrl, false, isLocalAddressAllowed),
 			signal: controller.signal,
 		});
 
diff --git a/packages/backend/src/server/api/endpoints/fetch-rss.ts b/packages/backend/src/server/api/endpoints/fetch-rss.ts
index ba48b0119e..562092ea07 100644
--- a/packages/backend/src/server/api/endpoints/fetch-rss.ts
+++ b/packages/backend/src/server/api/endpoints/fetch-rss.ts
@@ -7,6 +7,7 @@ import Parser from 'rss-parser';
 import { Injectable } from '@nestjs/common';
 import { Endpoint } from '@/server/api/endpoint-base.js';
 import { HttpRequestService } from '@/core/HttpRequestService.js';
+import { URL } from 'url';
 
 const rssParser = new Parser();