The invention provides a discharge lamp lighting device, a power supply device and an illuminator, which can prevent an overlarge electric stress on a circuit element or the discharge clamp after lighting the lamp. The device is provided with a direct current power supply part, a resonance part formed a resonance circuit together with the discharge lamp. A switch part for switching the DC power supply part and the resonance part, and a driving part for driving the switch part to output an alternated current to the discharge lamp from the resonance part through the voltage frequencies on two ends of a controlling capacitor. After the driving part is started and still cannot work in a preset stopping time T1, the driving part starts to work after stopping for the stopping time T1. The voltages on two ends of the capacitor can be stabled in the stopping time T1, so the overlarge electric stress on the circuit element or the discharge clamp can be avoided after starting, even if starting again after stopping for a short period of time.