PURPOSE: To facilitate the formation of a holder with a linking surface by feeding a molding material such as resin into a mold made up of a lens or a primary standard having the same surface as the surface for retaining the lens and a cylinder into which they are inserted.

CONSTITUTION: A lens with one side as a retaining surface 1 or a primary standard 2 having the same surface as the retaining surface are mounted into a cylinder 3. A molding material 5 such as resin is fed into the cylinder 3 and solidified. The molding is withdrawn from the cylinder 3 separating from the lens or the primary standard 2. Thus, a holder is obtained with a linking surface which retains the lens being worked with a linking.