Abstract: Provided is a transmission electron microscope capable of obtaining a hollow-cone dark-field image and visually displaying irradiation conditions thereof. The transmission electron microscope is provided with an irradiation unit for irradiating a specimen with an electron beam, an objective lens for causing the electron beam transmitted through the specimen to form an image, beam deflectors for deflecting the electron beam, said beam deflectors being positioned higher than a position where the specimen is to be placed, an objective movable aperture for passing only a portion of the electron beam transmitted through the specimen, and a deflection coil control unit.

Abstract: An electron microscope is provided that can automatically adjust the optical axis even in a state of deviation of the optical axis according to which the position of an electron beam on a fluorescent plate cannot be verified after replacement of an electron source. The microscope measures current of a fluorescent plate and determining whether the fluorescent plate is irradiated with an electron beam or not; without irradiation, controls a deflector to move the electron beam such that the fluorescent plate is irradiated with the electron beam; and, with irradiation, controls the deflector such that the current becomes a local maximum and a magnitude of luminance acquired from the image of the electron beam with which the fluorescent plate is irradiated becomes a local maximum.