Patent ID: 7312563

Claim:
A short arc lamp comprising: a lamp main body having a reflective surface therein, a first opening on an optical axis thereof, and a second openings; a window member provided so as to cover the second opening and to define a discharge space between the lamp main body and the opening; a first electrode and a second electrode that are arranged so as to face each other, wherein a tip portion of each of the electrodes extends into the discharge space; and a base disposed approximately at a back end portion of the lamp main body, wherein a hole is formed in the base, wherein an end portion of a first electrode is inserted in the hole of the base, and penetrates the first opening, wherein wax material is filled in between an inner circumferential surface of the base and a side surface of the first electrode, wherein the first electrode is held in a burying portion of the base, and wherein a diameter of the first electrode in the burying portion is larger than that of the tip portion of the first electrode, and an inner diameter of the first opening that the first electrode penetrates is smaller than that of a maximum diameter portion of the first electrode in the burying portion.