diff --git a/src/index.js b/src/index.js
index 935d8203..0cd15048 100644
--- a/src/index.js
+++ b/src/index.js
@@ -426,6 +426,9 @@ class ExtractCssChunks {
       this.traverseDepthFirst(rule, (node) => {
         if (node && node.use && Array.isArray(node.use)) {
           const isMiniCss = node.use.some((l) => {
+            if (typeof l === 'function') {
+              return false;
+            }
             const needle = l.loader || l;
             return needle.includes(pluginName);
           });
diff --git a/test/cases/function-loader/expected/main.css b/test/cases/function-loader/expected/main.css
new file mode 100644
index 00000000..aea53e43
--- /dev/null
+++ b/test/cases/function-loader/expected/main.css
@@ -0,0 +1,2 @@
+body { background: red; }
+
diff --git a/test/cases/function-loader/index.js b/test/cases/function-loader/index.js
new file mode 100644
index 00000000..aa3357bf
--- /dev/null
+++ b/test/cases/function-loader/index.js
@@ -0,0 +1 @@
+import './style.css';
diff --git a/test/cases/function-loader/style.css b/test/cases/function-loader/style.css
new file mode 100644
index 00000000..31fc5b8a
--- /dev/null
+++ b/test/cases/function-loader/style.css
@@ -0,0 +1 @@
+body { background: red; }
diff --git a/test/cases/function-loader/webpack.config.js b/test/cases/function-loader/webpack.config.js
new file mode 100644
index 00000000..0137a9e4
--- /dev/null
+++ b/test/cases/function-loader/webpack.config.js
@@ -0,0 +1,21 @@
+const Self = require('../../../');
+
+module.exports = {
+  entry: './index.js',
+  module: {
+    rules: [
+      {
+        test: /\.css$/,
+        use: [
+          () => ({ loader: 'css-loader' }),
+        ],
+      },
+    ],
+  },
+  plugins: [
+    new Self({
+      filename: '[name].css',
+      hot: true,
+    }),
+  ],
+};