An image forming apparatus includes: a first optical head group including first optical heads arranged in a sub-scanning direction; a second optical head group including second optical heads arranged in the sub-scanning direction and overlapping the first optical head group in a main scanning direction; a detector that detects displacement amounts between the first optical heads and the second optical heads; and a controller that performs registration based on the detection by the detector. The controller performs, with one of the first optical heads as a reference, registration on the other first optical heads, performs, with one of the second optical heads as a reference, registration on the other second optical heads, and performs registration between the first optical head group and the second optical head group based on a displacement amount between one of the first optical heads and one of the second optical heads.