This invention discloses an image processing apparatus that can obtain, from an image, the amount of correction for chromatic aberration of magnification, that can appropriately correct a color shift while suppressing a change in color on the edge portion of the image before and after the correction. In obtaining the amount of color shift between one color plane and another color plane, the color differences before and after the color shift is corrected are calculated for each pair of pixels included in regions of interest. It is determined whether the amount of change in color difference before and after correction falls within a predetermined range. The amount of color shift is obtained in the range in which it is determined that the amount of change in color difference before and after correction falls within a predetermined range.