With conventional optical axis adjustment, a charged particle beam will not be perpendicularly incident to a sample, affecting the measurements of a pattern being observed. Highly precise measurement and correction of a microscopic inclination angle are difficult. Therefore, in the present invention, in a state where a charged particle beam is irradiated toward a sample, a correction of the inclination of the charged particle beam toward the sample is performed on the basis of secondary electron scanning image information from a reflector plate. From the secondary electron scanning image information, a deviation vector for charged particle beam deflectors is adjusted, causing the charged particle beam to be perpendicularly incident to the sample. At least two stages of charged particle beam deflectors are provided.