A controller of an image forming apparatus calculates a density difference between a measurement result of a toner image having the highest density formed on a photosensitive drum, which is obtained by an image density sensor, and the highest density of a density target. When the density difference falls within a predetermined range, the controller generates a tone correction table based on a density value of a first toner image formed with a plurality of densities including the highest density, and sets, based on the density difference, an exposure amount of laser light to be applied to the photosensitive drum by an exposure device. When the density difference falls out of the predetermined range, the controller generates the tone correction table based on a density value of a second toner image having a larger number of tone levels than that of the first toner image.