There is disclosed a charged particle beam device which judges whether or not an image based on a dark-field signal has an appropriate atomic number contrast. Input reference information, a bright-field image or a back-scattered electron image is compared with a dark-field image, and it is judged whether or not a correlation value between them or the dark-field image has a predetermined contrast. According to such a constitution, it is possible to obtain information by which it is judged whether or not the dark-field image has an appropriate atomic number contrast.