To enable a lamp of a projector to move up and down safely with simple structure.

A generator loading portion on which an engine generator is loaded and a telescopic strut 20 are provided on a travelling cart, and the telescopic strut 20 has a hollow fixed strut 21 fixed to the travelling cart and a tip strut 24 on which a tip piston 38 moving up and down by hydraulic fluid 52 supplied to a fixed oil chamber 34 in the fixed strut 21 is mounted. A lamp pedestal provided with a lamp is mounted on the tip strut 24. The telescopic strut 20 extends when the hydraulic fluid 52 in an oil tank 51 incorporated in the traveling cart is supplied to the fixed oil chamber 34 by driving an oil pump 57, and it shrinks when the hydraulic fluid 52 is returned into the oil tank 51.