To increase rigidity, also facilitate manufacturing, thereby form a water drip shade at a low cost, by molding by a die to vulcanize material same as that of a jacket to form the water drip shade, having a diameter larger than that of the plural shade parts, on a given shade part out of plural shade parts extending in the radial direction from the outer periphery of a sheath part.

A jacket 3 is formed on the periphery of an FRP tube 2 by a conventional method. Then, a water drip shade part 6 is molded to be provided on a shade part 5-1, by mounting a die 21, wherein segments 21-1 and 21-2 dedicated to the water drip shade are combined, on a shade part 5-1 in a place where the water drip shade part 6 is to be formed; and filling the spaces of the shade part 5-1 and the die 21 with silicone rubber same as the jacket 3 to vulcanize the silicone rubber. After that, the die 21 is mold-released to obtain a polymer porcelain tube with a water drip shade. A core member can be suitably applied to a polymer insulator and an SP insulator, etc., composed of a solid FRP rod.