An image forming apparatus wherein a photosensitive drum is located such that its circumferential surface is exposed to light at a position between an image surface of light that is emitted from an LED at a distance of a half of a pitch of a plurality of rod lenses from a first rod lens of the plurality of rod lenses and that passes through the first rod lens and an image surface of light that is emitted from an LED at a distance of the pitch of the plurality of rod lenses from a second rod lens of the plurality of rod lenses and that passes through the second rod lens.