An image forming apparatus that includes an optical writing device for applying light corresponding to image data to form a first image of the image data includes: a temperature detecting unit that detects temperature at a plurality of positions in the optical writing device; and an adjustment processing unit that, when a temperature difference between the positions detected by the temperature detecting unit is out of a predetermined range, forms a second image for quality verification and performs a process for adjusting color registration of the first image by using the second image.