To provide a discharge lamp ignition device to light high-intensity discharge lamps in which, during alternating current ignition, the fluctuation of luminous flux on the reversal of polarity of the voltage impressed on the lamp is minimized and in which steady lighting characteristics of the discharge at startup are secured, a discharge lamp ignition device has a capacitor Ch connected to a transformer Th and an intermittent voltage impression arrangement Uj to drive voltage impression on the primary winding Ph, with the secondary winding Sh of the transformer Th constituted so that the voltage generated in the secondary winding Sh can be impressed overlapping the output voltage of an inverter Ui between the electrodes of the discharge lamp Ld by interposing it in the path connecting the output of the inverter Ui and the electrode for the main discharge of the discharge lamp Ld.