PURPOSE: To form at least one of both end surfaces of a spacer body into a slanting surface which slants at a proper angle to the axis of a bolt and to easily set the emission direction of light from each light emission dot body at low cost.

CONSTITUTION: The axis 16b of the bolt 16 is slanted at the proper angle θ1 to the axis of the light emission dot body 13, the rear end surface 13d of the light emission dot body 13 is set at right angles with the axis 16b, and one end surface 17b on the side of a panel plate 10 between both the end surfaces 17a and 17b of the spacer body 17 is slanted at a proper angle to a plane 19 perpendicular to the axis 16. Consequently, the bolt 16 is turned up to bring one end surface 17b of the spacer body 17 into contact with the top surface of the panel plate 10 and the rear end surface 13d of the dot body 13 into contact with the other end surface 17a of the spacer body 17. The dot body 13 can, therefore, be fitted slantingly at the specific angle θ to the surface 20 perpendicular to the top surface of the panel plate 10.