An electrodeless discharge lamp, including a waveguide for transmitting microwave emitted from a magnetron, a resonator positioned at an outlet port of the waveguide, for blocking the microwave and passing light and a united bulb, which is positioned inside the resonator, including a bulb portion which seals inert gas, and emits light by the microwave, and a reflective portion for reflecting the light emitted from the bulb portion forwards, which are integrally formed, can reduce assembly time of a lamp and reduce the whole size of a lamp.