A process cartridge detachably mountable to an electrophotographic image forming apparatus main body, including: an electrophotographic photosensitive drum; a cleaning member for removing developer adhering to the photosensitive drum; a removed developer containing portion for containing the developer removed by the cleaning member; a filter member mounted to the removed developer containing portion for allowing ventilation between the interior and exterior of the removed developer containing portion; a recess provided on the removed developer containing portion and covered with the filter member; and a communicating portion provided on the removed developer containing portion for communicating between the interior of the removed developer containing portion and the recess to ventilate therebetween.