PURPOSE: To bring a shielding cover and a frame body into contact under a stable state by forming a protruding section to at least one side of the opening edge of the conductive frame body and installing the conductive shielding cover onto the opening surface of the frame body.

CONSTITUTION: When a shielding cover 6 is mounted onto the opening surface of a frame body 3, the noses of the triangular protruding sections 5 of the frame body 3 and the underside 10 of the shielding cover 6 are brought into contact. Since size L1 is made longer than size L2 at that time, a clearance is formed in a size section L3. One sides 12 of the square holes 8 of the shielding cover 6 ride on slant faces 11 shaped to the conical protruding sections 7 of the frame body 3 and fitted, thus holding the shielding cover 8. Accordingly, there are the nose surfaces of the triangular protruding sections 5 in the opening edge of the frame body 3 and the underside 10 of the shielding cover 6 and the sides 12 of the square holes 8 of the shielding cover 6 and the slant faces 11 shaped to the conical protruding sections 7 of the frame body 3 as sections where the shielding cover 6 and the frame body 3 are brought into contact, and the sections where these shielding cover 6 and frame body 3 are brought into contact can be brought into contact positively.