diff --git a/include/mruby.h b/include/mruby.h
index 0541bc709..b3582541a 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -84,7 +84,7 @@ struct mrb_context {
   struct RProc **ensure;                  /* ensure handler stack */
   int esize;
 
-  uint8_t status;
+  enum mrb_fiber_state status;
   struct RFiber *fib;
 };