Abstract: An apparatus for preventing leakage of a material inside a bulb for a plasma lighting system comprises a bulb containing a discharge material therein for emitting light as the discharge material becomes a plasma state by an electric field, and a magnetic field forming portion for preventing the discharge material of a plasma state from being leaked by an external electric field of the bulb by forming a magnetic field at a peripheral portion of the bulb. The discharge material is prevented from being leaked out of the bulb even if the bulb is used for a long time, and thus a lifespan of the bulb is prolonged.