Abstract: A scanning electron microscope, comprises an electron gun, an electron-optical column which comprises an anode for accelerating the electrons, a specimen holder for accommodating and positioning the specimen to be examined being arranged underneath said column, and also a detector for detecting the electrons emerging from the specimen. The detector is connected to a display apparatus for the display of an image of the specimen by way of, for example, detected electrons. Between the electron-optical column and the specimen holder there is arranged a brake electrode. An adjustable voltage which reduces the velocity of the electrons emerging from the electron-optical column can be applied between the brake electrode and the anode.