There is a limit in range and distance in which an electron beam can interfere and electron interference is implemented within a range of a coherence length. Therefore, interference images are consecutively recorded for each interference region width from an interference image of a reference wave and an observation region adjacent to the reference wave by considering that a phase distribution regenerated and observed by an interference microscopy is a differential between phase distributions of two waves used for interference and a differential image between phase distributions of a predetermined observation region and a predetermined reference wave is acquired by acquiring integrating phase distributions acquired by individually regenerating the interference images. This work enables a wide range of interference image which is more than a coherence length by arranging phase distribution images performed and acquired in the respective phase distributions in a predetermined order.