An image forming apparatus is used together with a process cartridge which is detachably attachable to the image forming apparatus and which includes an electrophotographic, photosensitive body, a developing device provided with at least a developer containing portion for containing a developer and a developer carrying body for supplying the developer to the electrophotographic, photosensitive body as process devices acting on the electrophotographic, photosensitive body, and a memory device, and the image forming apparatus is constructed to execute a predetermined initial operation before formation of an image when it is determined that the process cartridge is in an early stage of use, based on information in the memory device. This structure provides an image forming apparatus and process cartridge capable of forming good images from the early stage of use of the process cartridge.