A process cartridge detachably mountable to an image forming apparatus includes a rotatable developer carrying member, a rotatable developer feeding member, a rotatable developer stirring member, a developer carrying member gear, a developer feeding member gear, a developer stirring member gear, a transmission member for transmitting a driving force to the developer carrying member, the developer feeding member and the developer stirring member, wherein the transmission member includes a first gear for transmitting the driving force to the developer carrying member gear, a second gear for transmitting the driving force to the developer feeding member gear, and a third gear for transmitting the driving force to the developer stirring member gear, in which the first gear, the second gear and the third gear are integrally molded.