There is provided an electron microscope in which a crossover position can be kept constant. The electron microscope (100) includes: an electron source (110) for emitting an electron beam; an acceleration tube (170) having acceleration electrodes (170a-170f) and operative to accelerate the electron beam; a first electrode (160) operative such that a lens action is produced between this first electrode (160) and the initial stage of acceleration electrode (170a); an accelerating voltage supply (112) for supplying an accelerating voltage to the acceleration tube (170); a first electrode voltage supply (162) for supplying a voltage to the first electrode (160); and a controller (109b) for controlling the first electrode voltage supply (162). The lens action produced between the first electrode (160) and the initial stage of acceleration electrode (170a) forms a crossover (CO2) of the electron beam. The controller (109b) controls the first electrode voltage supply (162) such that, if the accelerating voltage is modified, the ratio between the voltage applied to the first electrode (160) and the voltage applied to the initial stage of acceleration electrode (170a) is kept constant.