diff --git a/ractor.rb b/ractor.rb
index ef36b2937f..953d3ceddc 100644
--- a/ractor.rb
+++ b/ractor.rb
@@ -699,7 +699,7 @@ class Ractor
   def inspect
     loc  = __builtin_cexpr! %q{ RACTOR_PTR(self)->loc }
     name = __builtin_cexpr! %q{ RACTOR_PTR(self)->name }
-    id   = __builtin_cexpr! %q{ INT2FIX(rb_ractor_id(RACTOR_PTR(self))) }
+    id   = __builtin_cexpr! %q{ UINT2NUM(rb_ractor_id(RACTOR_PTR(self))) }
     status = __builtin_cexpr! %q{
       rb_str_new2(ractor_status_str(RACTOR_PTR(self)->status_))
     }