An ignitor semiconductor apparatus can include an output stage IGBT that controls the ON and OFF of the primary current of ignition coil, a sensing IGBT and a sensing resistance for detecting the current flowing through output stage IGBT, gate resistance and a current control circuit that detects the voltage across sensing resistance and controls the current flowing through output stage IGBT. First and second gate control circuits separately control the gate voltages of IGBT's such that the gate voltage of the output stage IGBT is higher than the gate voltage of the sensing IGBT, when the current flowing through output stage IGBT is larger than a predetermined current value, and such that the gate voltage of output stage IGBT is lower than the gate voltage of sensing IGBT, when the current flowing through output stage IGBT is smaller than the predetermined current value.