An image forming apparatus includes a plurality of image forming stations each having an image carrier and forming an image on the image carrier; a mark detecting unit for detecting a plurality of registration correction marks formed on a recording medium by the plurality of image forming stations; a correction mechanism for correcting a position difference between images formed by the plurality of image forming stations in accordance with a detection result by the mark detecting unit; and a controller for independently controlling an image forming operation of each of the plurality of the image forming stations so that the image density of each of the registration correction marks formed by the plurality of image forming units has a different predetermined image density.