In an image forming apparatus, a high-density portion and a low-density portion are arranged close to each other such that a boundary between the high-density portion and the low-density portion intersects with the conveyance direction of a density detection patch. A controller compares, in the conveyance direction, temporal change in the density detection value at a boundary portion shifting from the high-density portion to the low-density portion, with temporal change in the density detection value at a boundary portion shifting from the low-density portion to the high-density portion, and sets a process condition based on a result of the comparison.