An electrodeless lighting system includes: a resonator installed at an outlet of a waveguide guiding microwave energy generated from a magnetron and defining a cavity allowing light to pass therethrough while resonating microwave therein; a bulb positioned in the resonator and enclosing a radiation material for emitting light by the microwave energy; and one or plural microwave concentrating units installed at the inner circumferential surface of the resonator and concentrating microwave energy discharged from the outlet of the waveguide to the bulb. By concentrating microwave to electrodeless plasma bulb positioned inside the resonator, a stability in an initial lighting and light efficiency can be enhanced.