An air cushion manufacturing machine includes a film supply unit and a feed unit installed on a machine body and a sealing device for heat sealing an inflated double-layer film when the feed of the film stops. The manufacturing machine is characterized in that a solid state relay (SSR) is coupled to a power supply required by a heat sealer of the sealing device, and the solid state relay controlled by the processor compensates the heat loss of sealing according to the cycle of the sealing process, and a power-on time percentage is controlled to produce a punctuate periodic micro heating to the heat sealer and achieve a constant-temperature heat compensation for each sealing course of the heat sealer. The manufacturing machine is not affected by ambient temperature and is capable of improving the sealing effectiveness and overcome the drawback of conventional sealing devices that easily breaking an electrothermal wire.