An inclusion rating method includes carrying out a tensile test on a test specimen, which is made of a metallic material and charged with a hydrogen, to cause a fracture originating from a nonmetallic inclusion affected by the hydrogen in the test specimen, identifying a type of the nonmetallic inclusion, measuring a size of the nonmetallic inclusion, and evaluating a cleanliness of the metallic material by obtaining a distribution function of the size of the nonmetallic inclusion.