Discharge bulb

A discharge bulb for a vehicle, comprising:

• an arc tube;
• a glass shroud cylindrically surrounding the arc tube;
• and
• an insulated plug fixedly supporting an end portion of the glass shroud,
• wherein the arc tube including:
• a light generating portion having a discharge space therein;
• a first pinch seal portion and a second pinch seal portion, disposed on respective sides of the light generating portion;
• a first electrode rod protruding into the discharge space from the first pinch seal portion;
• and
• a second electrode rod protruding into the discharge space from the second pinch seal portion so as to be opposed to the first electrode rod,
• wherein a discharge light-emitting portion is formed directly from the first electrode to the second electrode,
• wherein the discharge space contains a rare gas and a metal halide, but does not contain mercury,
• the first electrode is made of thoriated tungsten, and
• the second electrode rod is made of pure tungsten.