To reduce the manufacturing cost of an optical element by engraving a fine structure on an optical element mold for molding the optical element and by transferring the fine structure having the same thin film function as in an antireflection film or the like on the surface of the optical element.

A tool 11 has a cutting edge with width of tooth smaller than the wavelength of light and performs a circular or elliptoid dummy rotational motion in a XZ plane by two translating actuators 21, 22. The fine structure having an antireflection effect by the cyclic configuration of a pitch smaller than the wavelength of the light is engraved on the work W by relatively moving the tool 11 to the workpiece W by a positioning device 10. The production efficiency of the optical element can be improved by molding the optical elements such as f θ lens having the antireflection effect by using the mold on which such the fine structure is engraved.