diff --git a/packages/zenn-markdown-html/__tests__/custom-syntax/embed/docswell.test.ts b/packages/zenn-markdown-html/__tests__/custom-syntax/embed/docswell.test.ts
index fe47bd6c..8cb4b506 100644
--- a/packages/zenn-markdown-html/__tests__/custom-syntax/embed/docswell.test.ts
+++ b/packages/zenn-markdown-html/__tests__/custom-syntax/embed/docswell.test.ts
@@ -8,7 +8,7 @@ describe('Docswell', () => {
         '@[docswell](https://www.docswell.com/slide/LK7J5V/embed)'
       );
       expect(html).toContain(
-        '<span class="embed-block embed-docswell"><iframe src="https://www.docswell.com/slide/LK7J5V/embed" allowfullscreen="true" width="620" style="border:1px solid #ccc;display:block;margin:0px auto;padding:0px;aspect-ratio:620/349"></iframe></span>'
+        '<span class="embed-block embed-docswell"><iframe src="https://www.docswell.com/slide/LK7J5V/embed" allowfullscreen="true" width="100%" style="border:1px solid #ccc;display:block;margin:0px auto;padding:0px;aspect-ratio:16/9"></iframe></span>'
       );
     });
   });
@@ -19,7 +19,7 @@ describe('Docswell', () => {
         '@[docswell](https://www.docswell.com/s/ku-suke/LK7J5V-hello-docswell)'
       );
       expect(html).toContain(
-        '<span class="embed-block embed-docswell"><iframe src="https://www.docswell.com/slide/LK7J5V/embed" allowfullscreen="true" width="620" style="border:1px solid #ccc;display:block;margin:0px auto;padding:0px;aspect-ratio:620/349"></iframe></span>'
+        '<span class="embed-block embed-docswell"><iframe src="https://www.docswell.com/slide/LK7J5V/embed" allowfullscreen="true" width="100%" style="border:1px solid #ccc;display:block;margin:0px auto;padding:0px;aspect-ratio:16/9"></iframe></span>'
       );
     });
   });
diff --git a/packages/zenn-markdown-html/src/embed.ts b/packages/zenn-markdown-html/src/embed.ts
index 4d25b6be..494746d8 100644
--- a/packages/zenn-markdown-html/src/embed.ts
+++ b/packages/zenn-markdown-html/src/embed.ts
@@ -89,7 +89,7 @@ export const embedGenerators: Readonly<EmbedGeneratorList> = {
     if (!slideUrl) {
       return errorMessage;
     }
-    return `<span class="embed-block embed-docswell"><iframe src="${slideUrl}" allowfullscreen="true" class="docswell-iframe" width="620" height="349" style="border: 1px solid #ccc; display: block; margin: 0px auto; padding: 0px; aspect-ratio: 620/349;"></iframe></span>`;
+    return `<span class="embed-block embed-docswell"><iframe src="${slideUrl}" allowfullscreen="true" class="docswell-iframe" width="100%" style="border: 1px solid #ccc; display: block; margin: 0px auto; padding: 0px; aspect-ratio: 16/9"></iframe></span>`;
   },
   jsfiddle(str) {
     if (!isJsfiddleUrl(str)) {