diff --git a/src/docker_util.rs b/src/docker_util.rs
index 7a6220b..c7f13fa 100644
--- a/src/docker_util.rs
+++ b/src/docker_util.rs
@@ -48,8 +48,8 @@ impl DockerCmd {
         self
     }
 
-    pub fn mirror(&mut self, mirror: &str) -> &mut Self {
-        self.mirror = Some(mirror.into());
+    pub fn mirror(&mut self, mirror: &Option<&str>) -> &mut Self {
+        self.mirror = mirror.map(|s| s.into());
         self
     }
 
diff --git a/src/main.rs b/src/main.rs
index c066990..3a41c95 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -54,7 +54,7 @@ fn main() {
     docker_cmd.add_volumn(&get_final_docker_registry(&docker_image), "/usr/local/cargo/registry");
     if let Some(mirror) = &crates_mirror.or(docker_build_config.mirror) {
         if mirror.to_lowercase() != "none" {
-            docker_cmd.mirror(mirror);
+            docker_cmd.mirror(&Some(mirror));
         }
     }
     docker_cmd.exec(&args).unwrap();