1. A method for reviewing defects of a semiconductor device, the method comprising the steps of: obtaining an image by using a scanning electron microscope, the image including a defect on the semiconductor device as detected by a detection device, and making a reference image from the image including the defect; detecting the defect, by comparing the image including the defect to the reference image made from the image including the defect; and wherein when the defect cannot be detected by comparing the image including the defect with the reference image made from the image including the defect, another reference image without any defects is taken using the scanning electron microscope, and then the another reference image is compared with the image including the defect, in order to thereby detect the defect.