Process cartridge, electrophotographic image forming apparatus, and electrophotographic photosensitive drum unit

A process cartridge comprises an electrophotographic photosensitive drum having a photosensitive layer at a peripheral surface thereof, and process means actable on the electrophotographic photosensitive drum. The process cartridge also includes a coupling member capable of taking a rotational force transmitting angular position for transmitting the rotational force for rotating the electrophotographic photosensitive drum to the electrophotographic photosensitive drum and a disengaging angular position in which the coupling member is inclined away from the axis of the electrophotographic photosensitive drum from the rotational force transmitting angular position.