diff --git a/mrbgems/mruby-compiler/core/parse.y b/mrbgems/mruby-compiler/core/parse.y
index b9b723112..8ec816a3b 100644
--- a/mrbgems/mruby-compiler/core/parse.y
+++ b/mrbgems/mruby-compiler/core/parse.y
@@ -5762,10 +5762,13 @@ parser_yylex(parser_state *p)
     is_float = seen_point = seen_e = nondigit = 0;
     p->lstate = EXPR_END;
     newtok(p);
-    if (c == '-' || c == '+') {
+    if (c == '-') {
       tokadd(p, c);
       c = nextc(p);
     }
+    else if (c == '+') {
+      c = nextc(p);
+    }
     if (c == '0') {
 #define no_digits() do {yyerror(NULL, p,"numeric literal without digits"); return 0;} while (0)
       int start = toklen(p);