PURPOSE: To prevent the generation of unevenness of rotation and the generation of deviation without using a flywheel by integrally providing a ring material, of which periphery is formed with a belt guide part or a gear, in a shaft supporting part through a rubber material installed inside of the ring material.

CONSTITUTION: In the case where this driving force transmitting member is used for a driven pulley 3 fitted to a photosensitive drum 2 of an electrostatic copy, this driven pulley 3 is formed by integrally providing a ring material 5, of which periphery is formed with a belt guide part 4 with gear, with a shaft supporting part 7 through a rubber material 6 fitted inside of the ring material 5. The shaft supporting part 7 is engaged for fixation with a side of a supporting shaft 8 fixed to the photosensitive drum 2. For example, in the case where oscillation frequency component is transmitted to the ring material 5 through a wrapping connector transmitting system, the oscillation frequency component is absorbed by the rubber material 6 to effectively restrict the transmission of the vibration and deviation to the shaft supporting part 7 and the supporting shaft 8.