Extra-high pressure discharge lamp

The invention provides a extra-high pressure discharge lamp capable of suppressing breakage of the intermediate portion which is the boundary of the electrode and the electrode axis portion with a long lamp life span and high reliability. The extra-high pressure discharge lamp, comprises an optical transparent light emitting section, sealing sections connected to the light emitting section, a pair of electrodes which face each other in the light emitting section, wherein one of the electrodes having a thick portion, a thin portion and an intermediate portion which is formed between the thick portion and the thin portion, wherein 0.15 mg/mm of mercury is enclosed in the light emitting portion, and wherein the number of crystal grains which exist on a cross section perpendicular to an axis of the one of the electrodes is three.