The filament structure comprises a filament with a coiled portion and an uncoiled portion. The elastic partitioning member prevents lubricating fluid that has leaked from a sliding portion of a piston of the hydraulic cylinder from flowing into the dry clutch. At least one of the positive-electrode terminal lead and the negative-electrode terminal lead has a surface covering layer made of a metal different from that of its terminal mother material. A method of manufacturing an information recording medium uses the concaveconvex form transferred by the imprinting method to manufacture an information recording medium. In a third step, the component that presents a failure risk is isolated. The label strip is provided on its upper side with an identification coding.