PURPOSE: To make it possible to acquire sufficient earthing at a desired position of a printed plate by inserting a metal pin and penetrating it to a through-hole stopper, contacting an elastic metal contact to a metallic lid, and fixing the other side end of the metal pin projecting in a space between a pattern surface and the metallic lid to the pattern surface.

CONSTITUTION: A metal pin 3 in which an elastic metal contact 33 is installed to one end of a metal rod 31 whose diameter is smaller than that of a through- hole 12, and a through-hole stopper 32 is installed at the position at a specific distance from the end of the metal rod 31, is inserted to the through-hole 12 arranged in an earthing pattern from a part-mounting surface and penetrated up to the through-hole stopper 32. While the elastic contact 33 is contacted to a metallic lid 21 at the part-mounting surface side of a printed plate 11, the other end side of the metal pin 3 projecting in a space formed by a pattern surface and a metallic lid 22 is fixed to the pattern surface, and the printed plate 11 is earthed to a metal case 17. As a result, a sufficient earthing can be acquired at a desired position of the printed plate 11.