A method for securing optical parts together with a ring member enclosing it and functioning as a balance weight and/or a lens guard member to a support member with adhesive. The ring member is provided therein with at least one groove formed through the wall of the ring member by cutting away one portion thereof, and the optical parts, the ring member and the support member are disposed so that the optical parts and the support member may be respectively positioned adjacent both ends of the groove, and those three members are secured with adhesive applied onto the groove. With the method, those three members are simply secured to one another in one process.