An electrophotographic photosensitive drum mounting method for mounting an electrophotographic photosensitive drum to a frame of a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, the method including the steps of (a) a first inserting step of inserting a first drum shaft provided at one end of the electrophotographic photosensitive drum into a first frame hole provided in a first projected portion at one end portion which is projected in a direction crossing with a longitudinal direction of a frame of the process cartridge at one longitudinal end of the frame of; (b) facing step of facing, while the first drum shaft is inserted into the first frame hole, the other end of the electrophotographic photosensitive drum to a second projected portion projected from the frame in a direction crossing with the longitudinal direction of the frame at the other longitudinal end of the frame, by moving the other end of the electrophotographic photosensitive drum; (c) a second inserting step of inserting a second drum shaft provided on a second cover at the other end into a second frame hole provided in a projected portion at the other end of the frame and then into a drum hole formed at the other end of the electrophotographic photosensitive drum, from an outside of the second frame hole; (d) a bearing member engaging step of fitting a bearing hole of a bearing member around the first drum shaft, and engaging the bearing member with the first frame hole; (e) a first cover coupling process of fitting first hole formed in a first cover provided at one end around the first drum shaft, and then connecting the first cover to the frame; and (f) a second cover coupling process of connecting the second cover to the frame.