The invention provides an ignition device having a high shielding-performance from electro-magnetic wave noise and the like, while being compact in size and enabling electric current securely to flow through electric circuits built in the ignition device. The ignition device includes a metal cup and a metal header for holding a plurality of electrode pins respectively insulated and closing the opening of the cup to integrate the header in the cup, and further includes, in the cup, ignition charge, an ASIC, a capacitor, and a heating element. The ASIC is electrically connected to the electrode pins, the capacitor and the heating element, respectively, and the heating element abuts against the ignition charge. The header is provided on its outer periphery with a metal flange for fixing the header to an installation body of the ignition device.