Scanning electron microscope

In a scanning electron microscope having the function of observing an attentional object on a specimen, an error in an in-focus position can be corrected at high speeds. When moving the field of view to an object to be observed on a specimen on which an electron beam is scanned, an error between an in-focus position indicated by a mechanism for measuring a height of surface of the specimen and an actual in-focus position is corrected on the basis of information concerning points which are among a plurality of measured points and are adjacent to the target observing point.