A system for inspecting a pattern shape operates to detect secondary electrons from a specimen by irradiation of a focused electron beam and perform arithmetic processing on this detected signal. The detected signal waveform is divided into a plurality of regions on the basis of a variation of the signal quantity. The size of the divided regions is used for quantitative evaluation of a three dimensional shape of the specimen. This system, especially by displaying measurement results of the pattern shape for each divided signal waveform (bottom width in the final shape, resist bottom width, etching shift quantity, and etching slope-angle component by the exposure), permits an easy check on which a component varies and how the component varies in all shape variations. With this arrangement, a pattern cross section information effective in determining etching process conditions can be acquired using images by an in-line SEM capable of nondestructive observation.