To provide a light device in which fragments of a super high voltage short arc discharge lamp or reflecting mirror are not scattered, and a projector is not damaged even when the reflecting mirror is cracked due to the burst of the super high voltage short arc discharge lamp.

In the central axis of the rotating direction of a reflecting mirror 12 constituted with glass, the super high voltage short arc discharge lamp 13 having a pair of electrodes 15 and 16 are fixed. The super high voltage short act discharge lamp is constituted by enclosing mercury of 100 mg/ml or more in its electric discharge container, and by welding at least finder 20 less soluble than a metal lath or glass constituting the reflecting mirror at the bottom side of the reflecting mirror from the rotating direction centering on the focal position of the reflecting mirror. With respect to other structures, the bottom side of the reflecting mirror is covered with a heat-resistant ceramic or a metal lath.