PURPOSE: To easily remove and install a lamp holding body at the time of lamp exchange by installing the holding body in contact with an equipment body with a fixing member.

CONSTITUTION: In the center parts of the both side surfaces of a lamp holding body 1, a through hole 22 for passing the screw cylinder 6 of an equipment body 1 is formed, so that when the holding body 11 is fitted to the fitting recessed part 5 of the body, the cylinder 6 is protruded downward of the holding body 11, and the holding body 11 is mounted to the body 2 by screwing a nut 23 for fixing thereto. A connector piece 24 is passed through a connector hole 8 and connected to a connector, and lamp socket parts 17, 19 are connected to the lighting circuit of a circuit base plate. When lamps 12, 13 are exchanged, the nut 23 is removed from the cylinder 6, whereby the lamps 12, 13 can be separated from the body in the state installed to the holding body 11. Hence, the lamp exchange can be facilitated.