To attain manpower saving manufacture by means of a resin which is not adhered with a solvent by tubularly extruding a molten resin while blowing gas inward, pressurizing or the like, the inside of an extruding machine side tube while mold- clamping the resin by means of a metallic mold before cooling it, linking an extrusion speed with metallic mold movement and integrally molding at least one function part.

A first metallic mold 6 is set at an original point position between an extruder 2 and a haul-off device 4. Then, the extruder 2 is operated and a molten synthetic resin is extruded to the inside of the metallic mold 6 while blowing gas to the inside. Then, after mold-clamping is executed by the metallic mold 6, the side of the extruder 2 is pressurized. At the same time, a rotary shaft 11 is rotated and the metallic mold 6 is linked with an extrusion speed to be moved in the arrow A direction. Then, it is cooled and is controlled y a pressure adjusting part 12. Thus, a molded article 5 where a negative pressure detecting part 8, a pump squeezing part 9 and a tube 15 are integrated can be molded. Manpower saving manufacture is attained by the solvent adhesion impossible resin.