Abstract: An ignitor includes a first transistor, a transformer, an ignition member, and a switching control member. The first transistor is activated in accordance with supply from a DC power supply to perform switching. The transformer has a primary winding through which a switching current flows via the first transistor, a secondary winding for generating high voltage when the switching current flows through the first winding, and a tertiary winding for generating a control output for controlling the switching of the first transistor in accordance with the high voltage generated in the secondary winding. The ignition member ignites a target object using the high voltage generated in the secondary winding of the transformer. The switching control member prolongs the ON time for the switching of the first transistor in accordance with a decrease in at least one of the ambient temperature and the power supply voltage.