PURPOSE: To restart a high-pressure discharge lamp instantly by applying to it the voltage from each transformer which generates pulse voltage different in width from the peak value.

CONSTITUTION: The capacitor 8 of a high voltage generating device 3 is charged by the output of a stabilized power source 2, and then, by closing a switch 7, the charge potential is discharged rapidly through transformers 4 and 5. The primary windings 41 and 51 of the transformers 4 and 5 generate pulse voltages by -Ldi/dt, and they are boosted and generated at the secondary windings 42 and 52. These pulse voltages are compound with a pulse voltage of a high peak value and a narrow width, and a pulse voltage of a low peak value and a wide width. By applying this pulse voltage to a discharge lamp 1, a glow discharge is started and then transferred to an arc discharge. Consequently, the discharge lamp 1 is started to light in a short time, and it is lighted instantly even when it is put out once and turned on immediately.