An image forming apparatus can include exposure units having light emitting elements, a forming unit which has a photoreceptor exposed by the exposure unit and forms an image on a body to be transferred, an acquisition unit for acquiring a tilt angle error between an approximated line of a first pattern formed by the forming unit based on exposure of one exposure unit and an approximated line of a second pattern formed by the forming unit based on exposure of another exposure unit, and an adjustment unit for adjusting at least one of a light emitting time lag of the light emitting elements and an angular error of the exposure units between the one exposure unit and the other exposure unit to restrain the tilt angle error.