The optical option attachment ring of the present invention includes a rotator having an abutting surface that projects inward from the inner circumferential surface of the ring body and abuts the front end of the lens barrel as well as an arcuate portion that follows the upper end of the abutting surface. The optical option attachment ring further includes a resilient member that applies an urging force to the rotator to rotate in the direction opposite to the above-mentioned rotation direction and a stopper that abuts at least one of the one end and the other end so as to restrict the rotation caused by the urging force of the resilient member.