A method for actuating a discharge lamp (LP), wherein in order to ignite the lamp a resonant circuit (L, C1) is brought into resonance or near resonance by the action of alternating current and as a result adjustment to give a predetermined amperage is performed by varying the frequency of the alternating current. For this purpose a measuring device transmits measured values of the amperage to means for controlling the frequency, and these means establish the frequency in dependence on the measured values. Before the ignition voltage is applied the electrodes of the lamp are pre-heated by the action on the resonant circuit of alternating current of a different frequency than when the lamp is ignited. During pre-heating a predetermined amperage is set by adjustment in that the means for controlling the frequency are already activated and the procedure is such that the measuring device obtains measured values of the amperage and transmits them to the means for controlling, these measurement values corresponding to an amperage which deviates in a predetermined manner from the amperage specified by measured values during ignition.