In the present invention, in order to realize both a reduction of an image detecting time and high quality image detection in a scanning electron microscope for measurement, inspection, defect review, or the like of semiconductor wafers, a low-magnification image is taken by using a large beam current; a high-magnification image is taken by using a small beam current; control amounts for correcting a change in luminance, a focus deviation, misalignment, and visual field misalignment of taken images, which are generated due to a variation of a beam current are saved in advance in a memory of an overall control system; and these amounts are corrected every time the beam current is switched, thereby making it possible to take the images without any adjustment operation after switching the currents.