A method and device for observing a specimen, in which a convergent electron beam is irradiated and scanned from a desired direction, on a surface of a calibration substrate on which a pattern with a known shape is formed, and a beam SEM image of the pattern formed on the calibration substrate is obtained. An actual direction of the electron beam irradiated on the surface of the calibration substrate is calculated by use of the information about an apparent geometric deformation of the known shape on the SEM image, and the actual direction of the electron beam to the desired is adjusted direction by using information of the calculated direction. The pattern with the known shape formed on the calibration substrate has a crystal plane formed by anisotropic chemical etching.