A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus includes a drum unit containing a movably connected to a developing unit containing a developing roller between a contact position where the roller contacts the drum and a spaced position where the roller is spaced from the drum, a drum coupler engaging a first main assembly drive transmitter transmitting a first rotational driving force to the drum, when the process cartridge is mounted to the main assembly, a shaft coupler transmitting a second rotational driving force with a deviation permitted between an axis of a second main assembly drive transmitter and an axis of the roller, from the second main assembly drive transmission member to the roller when the process cartridge is mounted to the main assembly.