Disclosed herein is a scanning electron microscope having a function for positioning an object point of an objective lens at a defined position even under an electronic optical condition in which it is difficult to accurately control the position of the object point of the objective lens. A deflector is provided to deflect an electron beam in order to detect the object point and located at a desired position of the object point of the objective lens. The deflector is not used to scan a sample with the electron beam. The scanning electron microscope has a function for automatically adjusting the position of the object point to ensure that the object point of the objective lens is located at the position of the object point detection deflector by using a characteristic in which a displacement of an image by the deflector is minimal when the object point is located at the position of the deflector.