PURPOSE: To omit the number of molding processes to a large extent by enabling molding by a means of a molding process increased in a speed as compared with a compression molding method, by a method wherein an inner layer molded product having been separately molded is received and mounted in a mold for molding an outer layer and rubber/plastic for the outer layer is injected and allowed to fill the mold from a gate while the mold is revolved to mold the outer layer so as to cover the molded product.

CONSTITUTION: A molded product wherein a reinforced insulating layer 2' containing an internal conductive layer 1' has been separately molded on a core 8' is set in a mold and unvulcanized semiconductor rubber is injected in a cavity 13 from the nozzle of an injection molding machine through the nozzle touch 9 source 10, runner 11 and gate 12 of the mold to fill the same. At the time of filling, by rotating the core 8' at a constant speed, a semiconductive rubber layer having a uniform thickness can be formed on the reinforced insulating layer 2'.