Disclosed is an image forming apparatus whereby waiting time (downtime), which is required for forming an image by automatic adjustment relating to image formation density or image formation position, is made shorter than in the prior art. When an image having a size equal to or less than a prescribed size is formed is formed in this apparatus, the image to be formed is placed on an image carrier in such a manner that a vacant area for forming an adjustment pattern can be reserved on the image carrier. As a result, automatic adjustment relating to image formation density or image formation position can be executed while an image is formed.