diff --git a/Gemfile b/Gemfile
index 9ccefced..292c54d5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,6 +11,7 @@ group :jekyll_plugins do
   gem 'jekyll-include-cache'
   gem 'jekyll-sitemap'
   gem 'jekyll-liquify'
+  gem 'jekyll-redirect-from'
 
   # No need this gem because we build by GitHub Actions and serve on Pages.
   # gem 'github-pages'
diff --git a/Gemfile.lock b/Gemfile.lock
index d9ec7ed6..88974641 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -104,6 +104,8 @@ GEM
       liquid
       logger
       redcarpet
+    jekyll-redirect-from (0.16.0)
+      jekyll (>= 3.3, < 5.0)
     jekyll-sass-converter (3.1.0)
       sass-embedded (~> 1.75)
     jekyll-sitemap (1.4.0)
@@ -218,6 +220,7 @@ DEPENDENCIES
   jekyll-feed
   jekyll-include-cache
   jekyll-liquify
+  jekyll-redirect-from
   jekyll-sitemap
   mini_racer
   rake
diff --git a/_config.yml b/_config.yml
index ea79b130..7491982f 100644
--- a/_config.yml
+++ b/_config.yml
@@ -26,6 +26,7 @@ registration: https://dojocon-japan.doorkeeper.jp/events/176163
 plugins:
   - jekyll-feed
   - jekyll-include-cache
+  - jekyll-redirect-from
   - jekyll-sitemap # This must be LAST to include contents generated by gems above
   - jekyll-liquify # This enable to use variables in frontmatter
 
diff --git a/_posts/2025-07-21-contest-terms.md b/_posts/2025-07-21-contest-terms.md
index 8d053bff..e12ed748 100644
--- a/_posts/2025-07-21-contest-terms.md
+++ b/_posts/2025-07-21-contest-terms.md
@@ -2,7 +2,8 @@
 layout: post
 title: DojoCon Japan 2025 プログラミングコンテスト 参加規約
 date: 2025-07-21T00:00:00 UTC+09:00
-permalink: /contests/terms.html
+permalink: /contests/terms/
+redirect_from: /contests/terms.html
 ---
 <img src="/img/common/coderdojo-nameplate.webp" loading="lazy" alt="DojoCon Japan Cover Photo"
   title="DojoCon Japan Cover Photo" class="mb-4" />
diff --git a/_posts/2025-08-02-contest-how-to-apply.md b/_posts/2025-08-02-contest-how-to-apply.md
index ae674747..f6b0da50 100644
--- a/_posts/2025-08-02-contest-how-to-apply.md
+++ b/_posts/2025-08-02-contest-how-to-apply.md
@@ -5,7 +5,8 @@ title-in-news-list: 『DojoCon Japan 2025 プログラミングコンテスト
 date: 2025-08-02T01:00:00 UTC+09:00
 categories: news
 tags: 企画
-permalink: /contests/how-to-apply.html
+permalink: /contests/how-to-apply/
+redirect_from: /contests/how-to-apply.html
 ---
 <style>
 img {
diff --git a/test-directory-structure.py b/test-directory-structure.py
index 63eb2753..c0e37684 100755
--- a/test-directory-structure.py
+++ b/test-directory-structure.py
@@ -1,4 +1,5 @@
 #!/usr/bin/python
+from html.parser import HTMLParser
 from pathlib import Path
 
 """
@@ -12,6 +13,39 @@
 """
 
 
+class Parser(HTMLParser):
+    """
+    <meta http-equiv="refresh"> を含むファイルを検査の対象から除外する
+    """
+
+    def __init__(self, *, convert_charrefs: bool = True) -> None:
+        super().__init__(convert_charrefs=convert_charrefs)
+        self.is_redirect = False
+
+    def handle_starttag(self, tag: str, attrs: list[tuple[str, str | None]]) -> None:
+        if self.is_redirect:
+            return
+
+        if tag != "meta":
+            return
+
+        for attr_name, attr_value in attrs:
+            if attr_name == "http-equiv" and attr_value == "refresh":
+                self.is_redirect = True
+                break
+
+
+def is_redirect(path: str) -> bool:
+    with open(path) as fp:
+        content = fp.read()
+
+    parser = Parser()
+    parser.feed(content)
+    parser.close()
+
+    return parser.is_redirect
+
+
 def main() -> int:
     allowed_names = ["index.html", "404.html"]
     errors = list[str]()
@@ -25,6 +59,9 @@ def main() -> int:
                 continue
 
             path = cwd.joinpath(file).as_posix()
+            if is_redirect(path):
+                continue
+
             errors.append(path)
 
     if 0 < len(errors):