A scanning reflection electron diffraction microscope causes a primary electron beam (4) from its electron gun (2) to be reflectively diffracted from a sample (7) and a diffraction pattern to be formed on fluorescent screen (9). An optical lens (10) reduces this diffraction pattern in size and forms its reduced image on a photoelectric surface (11), thereby producing an image-carrying electron beam. Deflected by a deflecting system including a deflecting coil (12) and a condenser coil (13), the image-carrying electron beam is detected by an electron-multiplier (15) such that a diffraction pattern is displayed on a cathode ray tube (19).