diff --git a/Runtime/WebViewComponent.cs b/Runtime/WebViewComponent.cs
index 5217987db3baa599405529b63cb2600368c4f71b..1862a6e392f8aae4ff98f747dc336d386c20e3cb 100644
--- a/Runtime/WebViewComponent.cs
+++ b/Runtime/WebViewComponent.cs
@@ -101,7 +101,7 @@ namespace bessw.Unity.WebView
             if (tab is not null)
             {
                 var size = new Vector2(viewPort.rect.width, viewPort.rect.height) * scaler.scaleFactor;
-                Vector2Int sizeInt = Vector2Int.RoundToInt(size);
+                Vector2Int sizeInt = Vector2Int.FloorToInt(size);
                 if (tab.Size != sizeInt)
                 {
                     _ = tab.SetSize(sizeInt);