PURPOSE: To enable a printed board to be grounded enough at an optional position by a method wherein a metal pin is inserted into a through-hole provided inside a ground pattern until one end of it reaches a through-hole stopper, the other end is held by a conductive metal pin retaining part, and an elastic metal contact section is brought into contact with a metal lid on a component mounting side.

CONSTITUTION: A conductive metal pin retaining section 4 is fixed to a metal lid 22 on a pattern face side of a printed board 11. A metal pin 3 is provided with a metal rod 31, which is small enough in diameter to penetrate through a through-hole 12 provided to a printed board 11, where an elastic metal contact part 33 is provided to one end of the rod 31 and a through-hole stopper 32 is provided to a part of the rod 31 separate from the end by a specified distance. The metal pin 3 is inserted into the through-hole 12 provided in the grounding pattern on the pattern side as far as the through-hole stopper 32, the elastic metal contact part 33 is brought into contact with a metal lid 21 on a component mounting face side of the printed board 11, and the other end of the metal rod 31 is held by the conductive metal pin retaining section 4 to ground the printed board to a metal case 17. By this setup, a printed board can be grounded sufficiently at an optional position.