METHOD FOR MANUFACTURING HEATING INSTRUMENT

PROBLEM TO BE SOLVED: To provide a method for manufacturing a heating instrument which can contribute to quality improvement by efficiently obtaining the required amount of a sheet material covering the heating instrument at a low cost and appropriately obtaining the heating instrument having desired heating characteristics, wherein both sides of the sheet material have different air permeability.SOLUTION: In a method for manufacturing a heating instrument 10 which includes a heating element 1 coated with an air-permeable sheet having openings, openings are continuously made in a long-length sheet raw material 41 by an opening means 43 and the air permeability of heating element opposing regions, which are parallel in at least width direction of the long-length sheet raw material 41, are made different from each other. The heating element opposing regions with different air permeability of the long-length sheet raw material 41 are arranged in both sides of the heating element 1, respectively. The long-length sheet raw materials, which are arranged in both sides of the heating element 1, are joined and the heating element 1 is enclosed.