A scanning electron microscope includes an electron-optical system including an electron source and an objective lens, a stage on which a sample is placed, a secondary electron detector disposed adjacent to the electron source relative to the objective lens and configured to detect secondary electrons, a backscattered electron detector disposed between the objective lens and the stage and configured to detect backscattered electrons, a backscattered electron detection system controller configured to apply a voltage to the backscattered electron detector, and a device-control computer configured to detect a state of an electrical charge carried by the backscattered electron detector based on signal intensity at the secondary electron detector when the primary electrons are applied to the sample with a predetermined voltage applied to the backscattered electron detector.