Abstract: The laser reference device consisting of a beam sender which radiates a laser beam and a beam receiver which receives a laser beam radiated from the beam sender and issues a signal in accordance with the position whereat a laser beam is received, the beam receiver being mounted, for example, on a working equipment on a working lorry to detect a vertical or horizontal deviation of the working equipment from a laser beam by means of the beam receiver so that it is allowed to work while tracing a laser beam by such a control as to correct the vertical or horizontal deviation of the working equipment in accordance with the signal transmitted from the beam receiver.