A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, the process cartridge includes an electrophotographic photosensitive drum; process means actable on the electrophotographic photosensitive drum; a cartridge frame; a drum shutter movable between a close position in which the drum shutter covers an exposed portion of the electrophotographic photosensitive drum which is exposed through the cartridge frame and an open position in which drum shutter is retracted from the close position to expose the portion of the electrophotographic photosensitive drum, the drum shutter having a first shutter portion rotatably supported on the cartridge frame and a second rotatably supported on the cartridge frame, wherein in the close position, the first shutter portion covers an upstream side of the exposed portion with respect to an opening direction in which the drum shutter moves from the close position to the open position, and the second shutter portion covers a downstream side of the exposed portion with respect to the opening direction, and wherein in the open position, the first shutter portion and the second shutter portion are overlapped with each other in the widthwise direction of the drum shutter.