Abstract: A film tubing device for use in a packaging apparatus comprising a former arranged in a transfer path of a continuous length of a heat-meltable film, the former including an inner former member on which the film is wrapped with its longitudinal side edges overlapping each other, the former further including an outer former member having a longitudinal outlet through which the overlapping side edges of the film project out, a pair of longitudinal sealers disposed adjacent to the longitudinal outlet as slightly spaced from the outer former member for nipping the overlapping side edges of the film, the sealers being heated for heat-sealing the overlapping side edges of the film, a thin air guide plate arranged between the outer former member and each sealer to define a clearance between the guide plate and the outer former member, and an air supplying nozzle for feeding cooling air into the clearance.