PURPOSE: To produce a resin tubular member having a large hollow ratio and uniform in wall thickness.

CONSTITUTION: A split type mold is equipped with a cavity 14 prescribing a resin tubular member 1 bent in a three-dimensional direction and the unnecessary parts 6, 7 integrally molded at both ends thereof. The mold is clamped and the leading end part of a core mold 13 is allowed to protrude to one end of the cavity 14 and a closure element 15 is sucked to a recessed part 13b to close a supply and exhaust hole 13a. A molten resin is injected in the cavity to form a bottomed cylindrical body so as to cover the core mold 13 having the closure element 15 sucked thereto and a pressure fluid is injected through the supply and exhaust hole 13a to form a hollow part and, at the same time, the closure element 15 is moved to the other end of the cavity in such a state that it is in contact with the inner leading end surface of the hollow part of the bottomed cylindrical body to mold a hollow molded product 21. After cooling, both unnecessary parts 6, 7 are cut off at both cutting parts A, B to obtain a resin tubular member.