Disclosed is an electrodeless lighting system capable of being used as an optical source of an electronic device by being minimized and capable of obtaining an optimum impedance matching and controlling a resonance frequency. The electrodeless lighting system comprises: a magnetron for generating microwave and having an antenna through which the microwave is outputted; a resonator having a resonance space where the microwave is resonated and having an inner diameter partially different along a path that the microwave passes; a bulb installed inside the resonator and having a light emitting material therein for emitting light by the microwave energy; and a microwave feeder of which one side is connected to the antenna and another side thereof is connected to the bulb, for guiding microwave to the bulb, in which a ratio of an outer diameter of the microwave feeder and a ratio of an inner diameter of the resonator corresponding to the outer diameter of the microwave feeder are varied along a progressive direction of the microwave.