To provide plastic products for medical treatment, such as vacuum blood taking tubes, which are improved in barrier characteristics effective for permeability of atm. air and steam.

A vacuum manifold device 22 has junctures 24, 26, 28, 30, 32 and a coupling port 34 consisting of a rubber grommet. These junctures respectively arrive at isolation gate valves 42, 44, 45, 48, 50. These valves are respectively connected to a gaseous monomer source, a gaseous oxidizing agent source 54, a vacuum pump 56, a vent filter 58 and a rare gas source 60. Further, the device has an external electrode system 62 and an energy source 64. After the tubes are produced by a tube forming method, such as injection molding, extruding by end capping, blow molding or injection blow molding, the apertures of the tubes are connected to the vacuum manifold device by the coupling port and are evacuated to vacuum; thereafter, the tubes are subjected to plasma vapor deposition.