PURPOSE: To provide a driving device for a photosensitive drum which can surely transmit rotational force and easily attach/detach the photosensitive drum.

CONSTITUTION: In the driving device for the photosensitive drum obtained by making a driving axis 1 penetrate into the inside of the photosensitive drum 2, a stopper 7 engaged with both of the axis 1 and a cylindrical body 5 being a driven axis on the drum 2 side freely attachably/detachably in an axis direction is provided. When the axis 1 is rotated, the rotation force of the axis 1 is transmitted to the stopper 7 engaged with the axis 1. The rotation force transmitted to the stopper 7 is transmitted to the cylindrical body 5 on the drum 2 side. Since the stopper 7 is engaged with both of the axis 1 and the cylindrical body 5 being the driven axis in the axis direction, slippage does not occur between the respective members and the rotation force of the axis 1 is surely transmitted to the drum 2 through the stopper 7.