A lamp lighting apparatus has a discharge drive circuit for supplying discharge current to the lamp, a voltage conversion circuit for boosting voltage from DC power and supplying the boosted voltage to the discharge drive circuit, and an arc discharge detecting circuit for detecting that a state of discharge of the lamp changes to arc discharge, and outputting an arc discharge transition signal to the voltage conversion circuit, wherein when the voltage conversion circuit receives the arc discharge transition signal which shows that the transition to the arc discharge does not take place, the voltage conversion circuit supplies a first voltage or higher to the discharge drive circuit, and when the voltage conversion circuit receives the arc discharge transition signal which shows that the transition to the arc discharge takes place, the voltage conversion circuit supplies a second voltage lower than the first voltage to the discharge drive circuit.