To improve surface precision of an optical element or a rotating axis symmetrical type curved surface of a die for this optical element under a cutting method, on the optical element and on the die.

The rotating axis symmetrical shape curved surface of a workpiece 9 is cut and worked while moving a working point of a tool 8 and the workpiece 9 in the crest direction of a cutting blade of the tool 8 by revolving the tool 8 within a specified area under the cutting method to cut and work the rotating axis symmetrical shape curved surface on the workpiece 9 by making the tool 8 a knife edge of which has the circular arc cutting blade contact with the rotated workpiece 9 by rotating the optical element or the die to form this optical element as the work 9.

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