diff --git a/test/ruby/test_jit.rb b/test/ruby/test_jit.rb
index b9b085c976..7b643a7c1c 100644
--- a/test/ruby/test_jit.rb
+++ b/test/ruby/test_jit.rb
@@ -912,6 +912,8 @@ class TestJIT < Test::Unit::TestCase
   def assert_eval_with_jit(script, stdout: nil, success_count:, min_calls: 1, insns: [], uplevel: 3)
     out, err = eval_with_jit(script, verbose: 1, min_calls: min_calls)
     actual = err.scan(/^#{JIT_SUCCESS_PREFIX}:/).size
+    # Add --jit-verbose=2 logs for cl.exe because compiler's error message is suppressed
+    # for cl.exe with --jit-verbose=1. See `start_process` in mjit_worker.c.
     if RUBY_PLATFORM.match?(/mswin/) && success_count != actual
       _, err2 = eval_with_jit(script, verbose: 2, min_calls: min_calls)
     end