Using information about the position, orientation, and shape of a crack appeared in a judged material and information about the structure of the judged material as parameters, the stress intensity factor K_I of the crack is found. Based on the stress intensity factor K_I, hydrogen embrittlement cracking of the judged material is judged. The crack growth rate and possibility of brittle fracture can be judged by comparing the stress intensity factor K_I with the critical stress intensity factor K_IH for crack initiation or the critical stress intensity factor K_IC-H for brittle fracture about the temper embrittled steel which absorbs approximately 2.0 ppm hydrogen.