PURPOSE: To enable the fixing performance of a resin-molded material and a pole material to be sufficiently secured without increasing a manufacturing cost by a method wherein the embedding fixing part of the pole material is heated to melt a powdered resinous material, the resultant molten resinous material is made to adhere to the embedding fixing part to form an adhesion layer thereon, and its adhesion layer is joined with a resinous material in a semi-molten state, which is injected from a die side.

CONSTITUTION: The embedding fixing part 31 of a pole material 3 in the state of a single substance is first heated locally to be embedded into a powdered resinous material 4. As a result, the powdered resinous material 4 in the periphery of the embedding fixing part 31 is melted due to heat thereof, and the resultant molten resinous material is made to adhere to the circumference of the embedding fixing part 31 to form a fusion deposition layer 5 with a predetermined thickness. Then, the pole material 3 having the deposition layer 5 formed on the embedding fixing part 31 thereof is set on a predetermined position in a blow molding die, and a semi-molten resinous material for blow molding is injected from the die side so as to position the pole material 3 on the predetermined position in the blow molding die. In such a state, the blow molding die is clamped to perform blow molding, and the semimolten resinous material and the adhesion layer 5 of the pole material 3 are closely contacted to each other by the clamping force of the blow molding die to fusion weld both of them integrally. Thereafter, the blow molding die is opened to remove a blow- molded product 1 from the interior of the die.