An image forming apparatus includes a transfer belt and a plurality of image forming units. The image forming unit includes a photosensitive drum and a charge elimination part. The charge elimination part of a predetermined image forming unit irradiates a downstream area of the primary transfer position on the photosensitive drum of the predetermined image forming unit with post-transfer charge elimination light and irradiates an upstream area of a primary transfer position on the photosensitive drum of the other image forming unit disposed on a downstream side of the predetermined image forming unit in the conveyance direction. A slit part is provided between the predetermined image forming unit and the other image forming unit for narrowing an irradiation width of the pre-transfer charge elimination light in a circumferential direction of the photosensitive drum.