PURPOSE: To shorten a cycle time of molding, by improving transfer properties of a plastic lens where thicknesses are different from each other at the central part and an outer circumferential part.

CONSTITUTION: The surface of a lens core 2 on the inside of a mold is plated concentrically and regularly with a plurality of kinds of metallic plated layers having thermal conductivities different from each other. The first metallic plated layer 3 having the lowest thermal conductivity is formed on a part corresponding to a thin part of the central part of a lens. The second metallic plated layer 4 having a higher thermal conductivity than that of the first metallic plated layer 3 is formed on the surface and a circumferential part of the first metallic plated layer 3. Similarly the third, fourth, fifth and sixth metallic plated layers 5, 6, 7 and 8 are formed in order with similar regularity.