An image forming apparatus includes a plurality of process units, a plurality of latent image carriers, an optical writing unit, an upper cover, and a pitch positioning member. The pitch positioning member including a plurality of abutting portions so as to regulate movements of the plurality of process units in the horizontal direction by abutting each of the plurality of process units. The pitch positioning member including a plurality of notches extending from an upper portion to a lower portion of each of the respective plurality of abutting portions with a predetermined pitch.