The present invention provides an image processing method which includes at least any one of image recording and image erasing, wherein a light irradiation intensity at a center position of the laser beam irradiated in the image recording is controlled; in the image recording, a first auxiliary line extended by a predetermined distance from a start point of each of image lines constituting an image in the opposite direction from the scanning direction and a second auxiliary line extended by a predetermined distance from an end point of each of the image lines in the scanning direction are prepared, and when the first and second auxiliary lines including an image line are continuously scanned, the image line is scanned with irradiating the laser beam, and the first and the second auxiliary lines are scanned without irradiating the laser beam to thereby record the image.