An integrated circuit for an air bag system is used in an air bag system having an ECU and a module case connected to the ECU and accommodating a gas generator and an air bag. In the air bag system, two bus lines passing through the ECU are provided to supply currents and the like, and individual gas generators accommodated in the module cases are connected operationally by conductors branched from the bus lines. Each of the igniters incorporated in the gas generator is an electric igniter which is provided with a heat generating portion and a priming coming in contact with the heat generating portion, and the igniter and the bus line are connected to each other through the conductors, and the integrated circuit provided in the igniter is recorded with information to exhibit required functions, and a current for igniting the priming is supplied to the igniters through a capacitor.