A secondary electron signal obtained from a specimen when the specimen is scanned with an electron beam is detected by a detector and a specimen image is displayed on a first display screen area of an image display unit on the basis of the detected signal. The specimen image is stored, as an image for observation position designation, in a storage unit together with a position of the image. A plurality of images at different positions on the specimen may be used as the image to be stored. One of the stored images is selected and read and displayed on a second display screen area. When a part of interest on the displayed image for observation position designation is selected, the specimen is horizontally moved so that a position of the part of interest may be positioned at the center of the first display screen area and an enlarged image of the part of interest may be displayed on the first display screen area. This facilitates view field search outside a view field range.