Abstract: An apparatus for attaching leaves of a film of a plastic material to laid flat workpieces made of a film of plastic material, consists of a frame with a plate or a table over which the workpieces are continuously conveyed by means of a conveyor device. In a gap of the table plate, there is arranged a pair of conveyor rollers mounted in the frame, and having a roller gap substantially aligned with the table surface; the bottom roller of the pair is a counterpressure roller and the top roller is a suction cylinder. A conveyor cylinder cooperating with the suction cylinder successively delivers the leaves to the suction cylinder. A fishtail nozzle directed towards the roller gap blows heated air into the roller gap in a controlled manner so as to weld the leaf to the workpiece. The suction roller prevents the conveyor cylinder from being heated by the hot air in an inadmissible manner.