diff --git a/router/subrouter.go b/router/subrouter.go
index fdf642a..5e55f56 100644
--- a/router/subrouter.go
+++ b/router/subrouter.go
@@ -98,7 +98,8 @@ func (sr *SubRouter) Group(path string, fn func(*Group)) {
 }
 
 func (sr *SubRouter) ServeFiles(path string, fs http.FileSystem) error {
-	const suffix = "/:filepath"
+	const param = "filepath"
+	const suffix = "/:" + param
 
 	if len(path) < 10 || path[len(path)-10:] != suffix {
 		return errors.New("path must end with "+suffix, "path", path) //////////////////////////////////////////////////
@@ -107,7 +108,7 @@ func (sr *SubRouter) ServeFiles(path string, fs http.FileSystem) error {
 	fileServer := http.FileServer(fs)
 
 	sr.Get(path, func(c *context.Context) error {
-		c.Request.URL.Path = c.Param("filepath")
+		c.Request.URL.Path = c.Param(param)
 		fileServer.ServeHTTP(c.Response, c.Request)
 
 		return nil