To eliminate the unevenness of speed of an image carrier belt by effectively reducing slip of the image carrier belt on a driving roll in an image forming device.

The image forming device is provided with the image carrier belt which is wound around the driving roll and a follower roll and is driven to run in accordance with rotation of the driving roll and a charging roll which is brought into contact with the outer peripheral surface of the image carrier belt and electrifies the image carrier belt, and the charging roll 8 is brought into contact with a part of the outer peripheral surface of the image carrier belt 4, where the image carrier belt 4 is brought into contact with the driving roll 1.