To satisfy characteristics of a heater having a specific areal resistance value corresponding to a bridge wire level by specifying a length and a width of the heater.

First, an insulating board 1 is coated entirely with a photoresist, exposed and developed. Then, a heater 2 and a primary electrode are formed at window opening positions of the photoresist, and then the photoresist is removed. And, the heater 2 is heat treated, and then executed with a protective film 5. Then, the board is formed in a rectangular state. The rectangular board is divided into individual pieces, and then nickel-plated electrode and a solder- plated electrode are executed for completion. The heater 2 having 20 to 40 m>(square) obtained in this manner is formed linearly with a width of 20 to 2 μm and a length of 0.9 to 1.5 mm. Thus, the igniter satisfies characteristics corresponding to a bridge wire level.