Patent ID: 8587199

Claim:
A discharge lamp unit comprising: a supporting member which supports a discharge lamp; circuit elements which supply electric power to the discharge lamp supported by the supporting member; and an electric wire which electrically connects the circuit elements and the discharge lamp through the supporting member, a housing case member accommodating the circuit elements and the supporting member so that a part of the supporting member is exposed to the outside of the discharge lamp unit; a circuit substrate placed at a bottom side of the housing case member; and a separation wall for dividing an inside space of the housing case member; wherein: the electric wire has a radiation part, and a surface area of the radiation part is larger per unit length than a part other than the radiation part in the electric wire; at least a part of the radiation part contacts with a hollow part formed in the housing case member; a part of the circuit elements is mounted on the circuit substrate, and the separation wall is formed between the supporting member and the circuit substrate so that the supporting member is separated from the circuit substrate, and the hollow part is formed between the separation wall and the circuit substrate; and the radiation part is formed in the separation wall so that a part of the radiation part is exposed to an inside space of the hollow part.