A photosensitive member cartridge 20, a developing cartridge 40, and a toner cartridge 60 can be mounted in and removed from a common mounting/removing opening 2a through a common path without enlarging the device. The mounting/removing opening 2a also can be made comparatively small. Thus, a configuration is simplified. The toner cartridge 60 can be mounted or removed by rotating a handle 62 to an upper direction. The developing cartridge 40 and the toner cartridge 60 can be mounted or removed by pressing down a handle 25. The photosensitive member cartridge 20, the developing cartridge 40, and the toner cartridge 60 can be individually exchanged depending on lifetime of the cartridges.