A discharge lamp lighting apparatus includes: an inverter circuit including a switch circuit and a high-voltage transformer; a step-up circuit connected at the input stage of the inverter circuit; a control circuit to output a switch circuit controlling signal and a step-up circuit controlling signal; an on-off switching circuit connected at a input voltage line; and a switch signal buffering circuit connected between the control circuit and the switch circuit and adapted to relay the switch circuit controlling signal. A drive voltage is applied to the control circuit without going through the on-off switching circuit, and a drive voltage is applied to the switch signal buffering circuit via the on-off switching circuit. With such a structure, an excess rush current is inhibited from flowing into the discharge lamp thereby preventing its electrode wear and therefore increasing the product life of a lamp and enhancing reliability while achieving cost reduction and downsizing.