An image forming apparatus includes a data recording unit to store a misregistration amount of a scanning line from an ideal scanning line when a plurality of laser beams is scanned in a main scanning direction, a calculation unit to calculate a shape of the scanning line based on the misregistration amount stored, and to determine a scanning line curvature cancellation curve which cancels misregistration of the calculated shape of the scanning line, and an image forming unit to form an image that reflects the scanning line curvature cancellation curve by shifting image data which is read out from a memory unit in a sub scanning direction according to the scanning line curvature cancellation curve. The image forming unit corrects the amount of misregistration which is smaller than a main scanning line interval by adjusting a transfer point at which the image data is shifted in the sub scanning direction.