A sulfur lamp including a power supply that supplies electrical power includes a transparent bulb having a space inside that contains sulfur. Additionally, a plurality of electrodes may be provided on an outside surface of the transparent bulb. Further, one end of each electrode may be connected to the power supply so that the sulfur is excited by an electric discharge to emit light. Therefore, the changing of sulfur contained in the space of the bulb into a plasma phase using the electrodes (not microwaves) avoids a need to use a magnetron, which has a low energy transfer rate, thereby increasing a system efficacy and saving a cost of replacing the magnetron with a new one.