diff --git a/time.c b/time.c
index c6cc0f6755..2630f735bf 100644
--- a/time.c
+++ b/time.c
@@ -4282,7 +4282,7 @@ time_floor(int argc, VALUE *argv, VALUE time)
 
     nd = NUM2LONG(ndigits);
     if (nd < 0)
-	rb_raise(rb_eArgError, "negative ndigits given");
+        rb_raise(rb_eArgError, "negative ndigits given");
 
     GetTimeval(time, tobj);
     v = w2v(rb_time_unmagnify(tobj->timew));