Abstract: The present invention relates to a method for fuse-bonding or fuse-bonding and fuse-cutting a plastic sheet by an electric heat wire. It is possible to use for manufacturing a shopping bag and an inflatable toy of polyethylene, but especially, a mold for manufacturing a balloon made of aluminum vapour deposition nylon and projections therefor, such as legs, can be simply manufactured. A nichrome circular wire 7 with a size according to a thickness of a sheet 5 to be worked is bent along a shape line of an object, such as balloon or the like, and covered with fluorine resin coated glass cloths 8 with an adhesive agent, which is used as a mold heater 4. The sheet 5 to be worked, silicone rubber 6 and the like are laminated on the mold heater 4, pressed by a press mechanism 1, and heated momentarily by applying electric current from a power source, and then cooled.