Abstract: The present invention provides a discharge lamp lighting system in which a discharge lamp is lighted by a commercial power source without using a choke transformer, electric power can be saved, and, in order to prevent a bad influence of high harmonic waves generated from the discharge lamp upon other electronic equipment, the impedance ratio resonating with the third high harmonic wave component of the power source is established between a capacitor and a choke coil provided between the discharge lamp and an alternate current power source to facilitate resonance of the third high harmonic wave component, and, when a starting lighting circuit is temporarily turned ON, the discharge lamp is lighted.