diff --git a/runtime/syntax/eruby.vim b/runtime/syntax/eruby.vim
index c20b086..4e175bc 100644
--- a/runtime/syntax/eruby.vim
+++ b/runtime/syntax/eruby.vim
@@ -22,7 +22,7 @@
   let s:lines = getline(1)."\n".getline(2)."\n".getline(3)."\n".getline(4)."\n".getline(5)."\n".getline("$")
   let b:eruby_subtype = matchstr(s:lines,'eruby_subtype=\zs\w\+')
   if b:eruby_subtype == ''
-    let b:eruby_subtype = matchstr(substitute(expand("%:t"),'\c\%(\.erb\|\.eruby\|\.erubis\)\+$','',''),'\.\zs\w\+$')
+    let b:eruby_subtype = matchstr(substitute(expand("%:t"),'\c\%(\.erb\|\.eruby\|\.erubis\)\+$','',''),'\.\zs\w\+\%(\ze+\w\+\)\=$')
   endif
   if b:eruby_subtype == 'rhtml'
     let b:eruby_subtype = 'html'