An electromagnetic clutch includes a rotating member; an electromagnetic coil that is arranged on a rotational axis of the rotating member and generates electro-magnetic force; an output mechanism that has an armature to which return force in a direction away from the electromagnetic coil is applied by a return spring; a cam mechanism that is juxtaposed along the rotational axis to the output mechanism, and has a control cam that is unable to rotate relative to the rotating member, and a cam follower that is able to roll between the control cam and the armature; and a relative rotation restricting device that is arranged on an axis of the cam mechanism, and that is configured to restrict relative rotation between the armature and the control cam when the electromagnetic coil is in a de-energized state.