PURPOSE: To keep the pressure balance of a carrying belt uniform when the carrying belt is knocked against the bottom face of a photosensitive drum by constituting the unit so that one of pivotally supporting parts catching a driving shaft on which a belt for carrying a transferred is stretched, can rock in the vertical direction with respect to the other pivotally supporting part.

CONSTITUTION: So that the driving shaft 4a of the belt 3 can rock in the vertical direction around a side 9a having a gear 10 as a drive connecting means, the other pivotally supporting part 9b is made into a vertically long hole. Therefore, even if a drum is inclined, follow-up with respect to the inclination can be attained, at the time of knocking the belt 3 and a transfer shaft 5 into the photosensitive drum by the action of a compressive spring 8.