To form an article having the cap lower portion of a back film and a portion welded to a cap film being flush with each other by providing a number of minute pores continued to a vacuum suction passage on the surface for executing vacuum suction, and placing a back film in close contact with the surface of a press roller.

The apparatus is formed such that one vacuum suction passage 42 is provided by setting, as a unit, a length made by dividing the circumference of a press roller into appropriate numbers, and each vacuum suction passage is connected to vacuum suction means at the moment of the film 2A being welded to the back film 2B within the range of time from an instant of the film 2A contacting the press roller 4 to the time of completing compression to the cap film. Concretely, a sliding plate 44 continued at a constant position is located on the vacuum suction passage 42 opened at one or both the ends of the press roller, and suction is done therethrough only when the opening of the vacuum suction passage 42 accords with the opening of the vacuum suction plate 45.