To exchange an electrifier at suitable time separately from the exchange of a process cartridge including a photoreceptor drum.

The process cartridge 2 is constituted by integrally assembling the photoreceptor drum 17, a developing device 24 and a cleaning device 23. The cartridge 2 is freely attached to/detached from an image forming device main body 1. The electrifier 3 is provided on the outside of the cartridge 2 on the main body 1 side. The electrifier 3 has a housing 3a, an electrifying roller 16 and a coating roller 15 coating the roller 16 with electrification accelerating particles 7, constitutes an electrifying cartridge as a whole, and is disposed while making a compression spring 6 intervene between the electrifier 3 and a frame 4 capable of retreating with a shaft 8 as center. Since the electrifier 3 is disposed on the outside of the cartridge 2, its exchanging time is properly set individually without being influenced by the exchanging time of the drum 17 or the like.