A cartridge (B) detachably mountable to a main body (A) of an image forming apparatus, the cartridge (B) comprising: a photosensitive drum ; a cleaning frame that supports the photosensitive drum so that the photosensitive drum is rotatable; at least one process member that acts on the photosensitive drum; wherein the cartridge is configured to be mounted with respect to the main body (A) of the image forming apparatus in a mounting direction of the cartridge that is parallel with a rotational axial direction of the photosensitive drum; a first position determination portion provided on a downstream side of the photosensitive drum in the mounting direction and having a first abutment portion , the first position determination portion being configured to determine a position of an axis of rotation of the photosensitive drum on the downstream side, with respect to the main body of the apparatus, in a direction orthogonal to the mounting direction by the first abutment portion abutting with the main body (A); and a second position determination portion provided on an upstream side of the photosensitive drum in the mounting direction and having a third abutment portion , the second position determination portion being configured to determine a position of an axis of rotation of the photosensitive drum on the upstream side, with respect to the main body of the apparatus, in the direction orthogonal to the mounting direction by the third abutment portion abutting with the main body (A), wherein in a cross section orthogonal to the mounting direction, a distance (Fy) from the axis of rotation of the photosensitive drum to the third abutment portion of the second position determination portion in a predetermined direction is larger than a distance (Ry) from the axis of rotation of the photosensitive drum to the first abutment portion of the first position determination portion in the predetermined direction, characterised in that the second position determination portion is provided on the cleaning frame . a photosensitive drum ; a cleaning frame that supports the photosensitive drum so that the photosensitive drum is rotatable; at least one process member that acts on the photosensitive drum; wherein the cartridge is configured to be mounted with respect to the main body (A) of the image forming apparatus in a mounting direction of the cartridge that is parallel with a rotational axial direction of the photosensitive drum; a first position determination portion provided on a downstream side of the photosensitive drum in the mounting direction and having a first abutment portion , the first position determination portion being configured to determine a position of an axis of rotation of the photosensitive drum on the downstream side, with respect to the main body of the apparatus, in a direction orthogonal to the mounting direction by the first abutment portion abutting with the main body (A); and a second position determination portion provided on an upstream side of the photosensitive drum in the mounting direction and having a third abutment portion , the second position determination portion being configured to determine a position of an axis of rotation of the photosensitive drum on the upstream side, with respect to the main body of the apparatus, in the direction orthogonal to the mounting direction by the third abutment portion abutting with the main body (A), wherein in a cross section orthogonal to the mounting direction, a distance (Fy) from the axis of rotation of the photosensitive drum to the third abutment portion of the second position determination portion in a predetermined direction is larger than a distance (Ry) from the axis of rotation of the photosensitive drum to the first abutment portion of the first position determination portion in the predetermined direction, characterised in that the second position determination portion is provided on the cleaning frame . <EOS>