To shift a weld line from the outermost side positions of the cylindrical parts made of a resin integrally molded on both ends of a rod-shaped part not only to enhance the strength of the cylindrical parts but also to ensure the strength of the rod-shaped part.

The shapes of the left and right cross-sectional part (1X and 1Y) with respect to an axial line are made asymmetric but made almost the same in cross-sectional area in the cross section in the direction corssing the longitudinal direction of the rod-shaped part (1) at a right angle. The cross-sectional shape of one of the cross-sectional parts (1X and 1Y) is formed into a shape reducing the flow resistance of the material injected from the gate (10) of a mold, the other cross-sectional shape thereof is formed into a shape increasing the flow resistance of the material, the length of the entire periphery of the cross-sectional part low in flow resistance is formed so as to become shorter than that of the entire periphery of the other cross-sectional shape, and the weld line is formed so as to be shifted from the outermost side regions of the cylindrical parts (2).