An electron microscope includes an electron source, a stage for mounting a specimen, an illuminating lens system that illuminates an electron beam onto the specimen, an imaging lens system that forms a specimen image using a reflecting electron beam of the illuminating electron beam, a beam separator that separates the illuminating electron beam and the reflecting electron beam, a control unit that controls current to be supplied to the beam separator; and a switching unit which enables switching between a first mode and a second mode. The control unit changes a value of the current to be supplied to the beam separator when switching from the first mode to the second mode.