An electric field for decelerating an electron beam is formed on a surface of a sample semiconductor to be inspected, an electron beam having a specific area (a sheet electron beam) and containing a component having such an energy as not to reach the surface of the sample semiconductor is reflected in the very vicinity of the surface of the sample semiconductor by action of the electric field for deceleration and then forms an image through an imaging lens. Thus images of plural fields on the surface of the sample semiconductor are obtained and are stored in image memory units. By comparing the stored images of the plural fields with one another, the presence and position of a defect in the fields are determined.