PURPOSE: To obtain a reflected electron beam image of uniform brightness distribution by generating a correction signal corresponding to the fluctuation of a direct current component included in a detected signal with the scanning of an electron beam over a wide range on the basis of a sweep signal for scanning an irradiated electron beam, and correcting the fluctuation of the direct current component in the detected signal.

CONSTITUTION: There is provided a correction signal generation means 11 for generating a correction signal corresponding to the fluctuation of a direct current component included in a detected signal with the scanning of an electron beam 5 over a wide range on the basis of a sweep signal for scanning the irradiated electron beam 5. According to the correction signal, the fluctuation of the direct current component in the detected signal is corrected. According to this system, the fluctuation of the direct current component in the detected signal with the scanning of the electron beam 5 is corrected using the correction signal, for obtaining a reflected electron beam image of extremely low magnification. The irradiated electron beam image, therefore, is free from excessive darkness or brightness. Consequently, it becomes possible to obtain an image of uniform brightness distribution.