Patent ID: 8350478

Claim:
A vehicle discharge lamp for emitting light according to a direct current turn-on system, comprising: an arc tube including a light emitter, and a cathode side fine tube and an anode side fine tube respectively disposed continuously with the light emitter on their mutual opposite sides with the light emitter between the cathode side fine tube and the anode side fine tube; a cathode side connecting rod having a portion disposed within the cathode side fine tube; an anode side connecting rod having a portion disposed within the anode side fine tube; a cathode side electrode disposed within the arc tube, with one end thereof in an axial direction being connected to one end of the cathode side connecting rod in an axial direction of the cathode side connecting rod; and an anode side electrode disposed within the arc tube, with one end thereof in an axial direction being connected to one end of the anode side connecting rod in an axial direction of the anode side connecting rod, wherein: the anode side fine tube includes an expansion portion formed in an end portion thereof existing on the light emitter side and an insertion portion formed continuously with the expansion portion and capable of receiving the anode side connecting rod therein; a portion of the anode side electrode is situated within the expansion portion, and a clearance is provided between an inner peripheral surface of the expansion portion and an outer peripheral surface of the anode side electrode; the expansion portion includes a uniform diameter portion in which an inside diameter thereof is set uniform in an axial direction of the anode side electrode; the light emitter includes a cylindrical-shaped flat portion in which a axial direction thereof is set coincident with the axial direction of the anode side electrode; and an inside diameter of the uniform diameter portion is set larger than an inside diameter of the insertion portion and smaller than an inside diameter of the flat portion.