There is provided an inflatable cushion filling machine for forming inflated packaging cushions from a roll of tubular thermoplastic material. The machine includes a film supply section and a cushion forming section. The cushion forming section includes means for delivering the tubular material through the cushion forming section; means for applying tension to the web of tubular material while air is being introduced into the tubular material. Means are provided for introducing air into the area between the tension means to fill the cushion. When filled, a sealing band, displaced transversely across the inflated tubular thermoplastic material, seals the lower end to form the top of one cushion and the bottom of the next cushion. Prior to forming the cushion, the walls of the tubular material separate from each other by the residual air from the filling operation of the previous cushion. A perforation knife may be provided to separate each cushion from the next succeeding cushion.