The present invention provides a registration correction method for image processing, by which location deviations among images with different behaviors such as visible ray images and invisible ray images can be corrected. According to this method, one of a visible ray image and an invisible ray image is designated as a reference image, and the other as an object image. A reference window is set within the reference image, and an object window of the same size as the reference window is set within the object image. While the object window is shifted by the pixel within the object image, the differential values of the brightness in the x-axis and y-axis directions of each pixel in the reference window and the object window are obtained. The object point where the total of the squares or the absolute values of the differences between the differential values of the reference window and the object window becomes smallest is set as the point corresponding to the reference point of the reference window. Thus, the visible ray image and the invisible ray image are matched with each other, with a plurality of points each determined in the above manner being the reference points for the matching.