An image forming apparatus for forming an image on a recording material, wherein a cartridge including at least a photosensitive drum is detachably mountable to said image forming apparatus, said image forming apparatus includes a first abutting portion, provided in an upstream side with respect to a mounting direction in which the cartridge is moved in its longitudinal direction to be mounted to said apparatus; a first urging means, provided in an upstream side with respect to the mounting direction, for urging, when the cartridge is mounted to said apparatus, the cartridge, in a direction crossing with a center axis of the photosensitive drum to position the cartridge in the crossing direction; a second abutting portion, provided in a downstream side with respect to the mounting direction; and a second urging means, provided in a downstream side with respect to the mounting direction, for urging, when the cartridge is mounted to said apparatus, the cartridge, in a direction crossing with the center axis of the photosensitive drum to position the cartridge in the crossing direction, wherein said first abutting portion and said second abutting portion are disposed opposite from each other with respect to a plane including the center axis.