There is provided an electron microscope capable of easily achieving power saving. The electron microscope (100) includes a controller (60) for switching the mode of operation of the microscope from a first mode where electron lenses (12, 14, 18, 20) are activated to a second mode where the electron lenses (12, 14, 18, 20) are not activated. During this operation for making a switch from the first mode to the second mode, the controller (60) performs the steps of: closing a first vacuum gate valve (50), opening a second vacuum gate valve (52), and vacuum pumping the interior of the electron optical column (2) of the microscope by the second vacuum pumping unit (40); then controlling a heating section (26) to heat an adsorptive member (242); then opening the first vacuum gate valve (50), closing the second vacuum gate valve (52), and vacuum pumping the interior of the electron optical column (2) by the first vacuum pumping unit (30); and turning off the electron lenses (12, 14, 18, 20).