One embodiment of the present invention is a driving device including a first member connected to a driving source and moved in a circumferential direction about a predetermined axis by a driving force from a driving source, a first member movable in a circumferential direction around a predetermined axis A second member disposed between the first member and the second member and positioned so as to be positioned on a locus of movement of the first member in the circumferential direction, and a second member disposed between the first member and the second member, And a mark provided on the covering member and indicating a state change of a contact surface between the covering member and the second member.本発明の一実施形態は、駆動源に接続され、駆動源からの駆動力によって所定の軸を中心に周方向に移動される第1の部材と、所定の軸を中心に周方向に移動可能で、かつ、第1の部材の周方向の移動軌跡上に位置するように配置される第2の部材と、第1の部材と第2の部材との間に配置され、少なくとも第2の部材に接触する、可撓性を備えた被覆部材と、被覆部材に設けられ、被覆部材における第2の部材との接触面の状態変化を示す指標とを具備する駆動力伝達機構である。
