To reduce effect by the temperature on a detection circuit and to improve the reliability by constituting a current control circuit which is a protective circuit of an element and one of the protective function of a one-chip igniter by a self-separation type N-MOS transistor, and providing a diode in a current control circuit part.

The bias voltage is applied to an input stage of a current control circuit by the forward voltage of diodes 28, 29 pulled-up by a resistor 27. The relationship between the current and the detected voltage is constant by make a setting so that the temperature factor of the forward voltage of the diodes is zero to the temperature factor of a load element for detecting the gate threshold voltage and the current of an N-MOS transistor 23, and the current detection without any temperature factor becomes possible. Because a current control circuit part consists of the self-separation type N-MOS transistor 23, it can be easily manufactured in the PNPN semi-conductor structure to constitute IGBT, and a highly reliable one-chip ignitor can be provided.