A heavy transformer is essential to an impulse heat sealer because the heater wire is short and wide. However, when thin slits are made in the strip heater wire from the opposite sides and the strip heater wire is elongated in zigzag, the transformer can be eliminated. However, in order to use the elongated heater wire in countries using a rated voltage of 200-240V without risk, such a structure that a hand does not touch the bare heater wire semipermanently, generated heat comes out quickly on the surface and disappears is required. A ceramics thin plate of good heat conductor and electrical insulator consisting of aluminum nitride, for example, and having a thickness of 0.6 mm is placed on the heating portion of a zigzag heater wire of a metal resistor thin plate, the entire periphery is surrounded by a thermal electrical insulator such as a glass cloth while leaving the upper surface thereof, and then the whole is made to adhere and fixed onto the heat dissipation base. The good heat conductor and electrical insulator is further reinforced with a heater reinforcement, as required.