A firing circuit for discharge lamps has a DC supply circuit (3) whose input stage contains a coil (7) and a condenser (8); an inverter (4) which converts the output voltage of the DC supply circuit into an alternating voltage and applies this alternating voltage to a discharge lamp; and a firing device (5) which generates a firing pulse for the discharge lamp. There is a control device (6) which executes a variable control for the output voltage of the DC supply circuit in the way that it executes a voltage-increasing operation, in order to raise that voltage in a load-free state to a specified voltage while the firing pulse generated by the firing circuit is applied to fire the lamp.
