A power saving apparatus is provided for an assisting apparatus that uses power from a rotating member to assist the operation of a bicycle transmission. The power saving apparatus comprises a rotating member engaging member that moves between a rotating member engaging position and a rotating member disengaging position, a setting mechanism that sets the rotating member engaging member toward the rotating member engaging position, and a power saving unit. The power saving unit saves power communicated between the setting mechanism and the rotating member engaging member when the setting mechanism attempts to move the rotating member engaging member into the rotating member engaging position and the rotating member engaging member encounters a force that resists the rotating member engaging member being in the rotating member engaging position.