A process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The apparatus includes an electrophotographic photosensitive member, a developing roller, two units, a movable member, and a cover. The roller can contact the photosensitive member to develop an image formed thereon. One unit supports the photosensitive member with a part thereof exposed. The other unit supports the roller and moves between positions for contacting the roller and the photosensitive member with each other and spacing these elements from each other. The movable member moves the roller-supporting unit between the contact and spaced positions. The cover covers the exposed part and engages the movable member to regulate movement thereof with the developing unit positioned in the spaced position.