A method of igniting a fuel-air mixture in a cyclically operating internal combustion engine comprising one or more combustion chambers (1) delimited by walls (2, 3, 4) at ground potential, using ignition means comprising The ignition electrode (5) in the chamber (1), in this method an electric oscillating circuit connected to the secondary side (17) of the DC / AC converter (12) is excited by the electric DC / AC converter (12) ( 7), wherein the ignition electrode (5) cooperates with the walls (2, 3, 4) of the combustion chamber (1) to form a capacitor, and the ignition electrode (5) is electrically insulated from the walls (2, 3, 4) through the insulator (6) is guided through one of the walls (2, 3, 4) of the combustion chamber (1) to extend into the combustion chamber (1), and the excitation of the oscillating circuit (7) is controlled to the ignition in each combustion chamber (1) The electrode (5) generates a corona discharge (22) that ignites the fuel-air mixture. According to the invention, combustion residues that have deposited on the surface of the insulator (6) in the combustion chamber (1) are removed from time to time using a combustion process and / or an electroerosion process.