A process cartridge transportable when mounted in a main assembly of an electrophotographic image forming apparatus. The cartridge includes an electrophotographic photosensitive drum, a developing roller for developing an electrostatic latent image on the drum when in contact with the drum, a drum unit supporting the drum, a developing unit supporting the roller and connected with the drum unit for rotation between a contact position in contact with the drum and a separated position, a force receiving portion for receiving, from the main assembly, a force for moving the developing unit from the contact to the separated position, with the cartridge mounted in the main assembly, a separation member for maintaining the developing unit at a position where the developing roller and the drum are separated from each other, and a detection portion to detect the mounting of the separation member when the cartridge mounted in the main assembly.