By use of charged particle beam images picked up in different conditions, a positional displacement caused by parallax is analyzed, and an optics of an apparatus for charged particle beam microscopy is corrected automatically. An analysis method using phase difference of Fourier transform images and having analytic accuracy lower than that for one pixel is adopted for the displacement analysis. In addition, a degree of coincidence between images calculated in this analysis method is used as a criterion for evaluating the reliability of an analysis result. Since the analysis method based on parallax is low in specimen dependency, the operation range is expanded. In addition, by adopting a high-accuracy displacement analysis method, the apparatus correction accuracy is improved by one digit. A malfunction preventing flow is added using the degree of coincidence as a judgement criterion. Thus, the apparatus can deal with unmanned operation. In addition, the degree of coincidence can be used as a monitor of inspection states or a record of states in an inspection apparatus.