Charged particle beam apparatus and displacement detecting circuit

An object of this invention is to provide a charged particle beam apparatus that can easily evaluate the stability of a position that is irradiated with a charged particle beam.To achieve the above object, this invention includes a detector that scans a charged particle beam and detects secondary particles that originate from a substrate, and an image processer that displays an image of the substrate on a display based on the secondary particles that are detected by the detector. The image processer is configured to display on the display any two or more members of the group consisting of a scanning image produced by the charged particle beam of the substrate, a wave in time domain showing fluctuations of the irradiation position of the charged particle beam on the substrate, and a power spectrum of the wave in time domain.