TWI757793B

An object of the invention is to provide an ion beam device that can measure structures existing at different positions in a thickness direction of a sample. The ion beam device according to the invention irradiates a sample with an ion beam obtained by ionizing elements contained in a gas. After obtaining a first observation image of a first shape of a first region using a first ion beam, the ion beam device processes a hole in a second region of the sample using a second ion beam, and uses the first ion beam on the processed hole to obtain a second observation image of a second shape of the second region. By comparing the first observation image and the second observation image, a relative positional relation between the first shape and the second shape is obtained (refer to FIG. 7C).