A process cartridge (703, 803, 903, 903', 903", 1003, 1103, 1103', 1103") to be mounted in an image forming apparatus body, the process cartridge comprising: a casing; and a photosensitive drum unit that is arranged inside the casing, wherein the photosensitive drum unit includes a photosensitive drum and an end member which is arranged in at least one end of the photosensitive drum, wherein the end member includes a preferably tubular bearing member and a shaft member which is held by the bearing member, wherein the shaft member includes a turning shaft which is movable in an axial line direction, wherein the casing is provided with a recessed operation portion (703b, 803b, 903b, 903'b, 903"b, 1003b, 1103b, 1103'b, 1103"b) operable by a user when drawing out the process cartridge from the image forming apparatus body, and characterized in that the operation portion is provided with an oblique detachment encouraging means in a recessed part corresponding to a drive side of the end member where the shaft member is provided for engagement with a drive shaft of the image forming apparatus body, or corresponding to a non-drive side opposite to the side of the end member where the shaft member is provided, away from a center of the process cartridge in a width direction that is a direction extending an axial line of the photosensitive drum unit, the oblique detachment encouraging means being provided for encouraging a user so as to hold the non-drive side portion and perform an operation at the non-drive side portion, wherein, in use, for detachment of the process cartridge from the image forming apparatus body, the end member is inclinable at an angle α being formed between the axial line of the photosensitive drum unit and the axial line of the drive shaft of the apparatus body, the angle a ranging from 1.5° to 10°. a casing; and a photosensitive drum unit that is arranged inside the casing, wherein the photosensitive drum unit includes a photosensitive drum and an end member which is arranged in at least one end of the photosensitive drum, wherein the end member includes a preferably tubular bearing member and a shaft member which is held by the bearing member, wherein the shaft member includes a turning shaft which is movable in an axial line direction, wherein the casing is provided with a recessed operation portion (703b, 803b, 903b, 903'b, 903"b, 1003b, 1103b, 1103'b, 1103"b) operable by a user when drawing out the process cartridge from the image forming apparatus body, and characterized in that the operation portion is provided with an oblique detachment encouraging means in a recessed part corresponding to a drive side of the end member where the shaft member is provided for engagement with a drive shaft of the image forming apparatus body, or corresponding to a non-drive side opposite to the side of the end member where the shaft member is provided, away from a center of the process cartridge in a width direction that is a direction extending an axial line of the photosensitive drum unit, the oblique detachment encouraging means being provided for encouraging a user so as to hold the non-drive side portion and perform an operation at the non-drive side portion, wherein, in use, for detachment of the process cartridge from the image forming apparatus body, the end member is inclinable at an angle α being formed between the axial line of the photosensitive drum unit and the axial line of the drive shaft of the apparatus body, the angle a ranging from 1.5° to 10°.