Charged particle beam equipment enables the simultaneous measurement and correction of magnification errors in both X and Y directions in one measurement without requiring the elimination of displacement, if any, in rotation direction between the direction of a periodic structure pattern of a sample having a known periodic structure and the X or Y direction on an electron image of the sample. The charged particle beam equipment of the invention enables the simultaneous measurement of magnification errors in the X and Y directions by FFT transformation and coordinate transformation of an electron image, even when there is a displacement in rotation direction between the direction of the periodic structural pattern and the X or Y direction on the electron image of the sample.