diff --git a/.changeset/itchy-rice-allow.md b/.changeset/itchy-rice-allow.md
new file mode 100644
index 000000000..812f2e5ac
--- /dev/null
+++ b/.changeset/itchy-rice-allow.md
@@ -0,0 +1,5 @@
+---
+"@4design/for-ui": patch
+---
+
+fix(Button): ローディングアイコンの色とサイズを修正
diff --git a/packages/for-ui/src/button/Button.tsx b/packages/for-ui/src/button/Button.tsx
index 8c68498fb..cbd3733fc 100644
--- a/packages/for-ui/src/button/Button.tsx
+++ b/packages/for-ui/src/button/Button.tsx
@@ -236,7 +236,11 @@ const _Button = <As extends ElementType = 'button'>({
       {endIcon}
       {loading && (
         <div className={fsx(`absolute inset-0 grid h-full w-full place-items-center`)}>
-          <Loader className={fsx(`[&:is(svg)]:fill-shade-dark-default [&:is(svg)]:h-6 [&:is(svg)]:w-6`)} />
+          <Loader
+            className={fsx(
+              `[&:is(svg):is(svg)]:fill-shade-dark-default [&:is(svg):is(svg)]:h-6 [&:is(svg):is(svg)]:w-6`,
+            )}
+          />
         </div>
       )}
     </MuiButton>