PURPOSE: To improve the productivity of the optical disk by providing the stamper for the optical disk having the metallic surface layer on which a rugged pattern having the film stress within a specified range is impressed.

CONSTITUTION: The sputtered film having about 1000 thickness is formed by using a specified high purity Ni target by DC power source. When a conductive film is formed, film-forming planting power is, for example, 200, 600 and 1000 W and the pressure in a device by the gaseous Ar flowing in at the time of film-forming is, for example, 0.3, 0.6 and 0.9Pa as a film-forming condition. Then, electroforming, peeling and the rear side processing of an internal diameter and an external diameter is executed to fashion as the stamper. The stamper obtained in such a way is set in the mold for injection molding, and the substrate consisting of the resin material such as polycarbonate is produced. In this case, durability is good when film stress is (-40)-(+40)kg/mm2. Therefore, the stamper excellent in durability is obtained, and using the stamper, the productivity of the optical disk is increased.