An igniter includes a switch element and a switch control apparatus. An ignition signal IGT is input to an input line of the switch control apparatus. A high-frequency filter removes high-frequency noise from the input line. A voltage comparator compares an output voltage VFIL of the high-frequency filter with a reference voltage VREF, so as to generate a judgment signal SDET. A driving stage controls an on/off switching operation of the switch element according to the judgment signal SDET. An off-state dead-time circuit prohibits the switch element from turning off during a predetermined dead time after the judgment signal SDET transits to a negated level that corresponds to the off state of the switch element.