diff --git a/error.c b/error.c
index f972ac807b..104e659dde 100644
--- a/error.c
+++ b/error.c
@@ -3134,7 +3134,7 @@ syserr_eqq(VALUE self, VALUE exc)
 /*
  * Document-class: fatal
  *
- * fatal is an Exception that is raised when Ruby has encountered a fatal
+ * +fatal+ is an Exception that is raised when Ruby has encountered a fatal
  * error and must exit.
  */