PURPOSE: To disuse the pipe between a controller and a headlight for reducing the repairing cost of a titled device by operating a hydrostatic controller of the headlight by means of an electric motor to be freely attached on and detached from this hydrostatic controller.

CONSTITUTION: A hydrostatic circuit 11 to drive a headlight is composed of a hydrostatic controller 12, a hydrostatic driving part 13, and hydrostatic pipes 14a and 14b. In the hydrostatic controller 12, a piston part 18 is provided to be moved forward and backward by the rotatiin of a screw 19 for changing the amount of pressurized liquid in hydrostatic chambers 15a and 15b. Through this changing, a driving piston 25 in the hydrostatic driving part 13 is reciprocated by the work of a return spring 26. To an electric motor 31 to drive the hydrostatic controller 12, a reduction gear 32 and a control part 33 are added. Besides, the screw 19 is connected by key with the output shaft inside a control part 33. A flange 16 provided in the hydrostatic controller 12 is connected with the control part 33 by a screw 38.