PURPOSE: To have the earth assuredly only at the area between a core and a shielding case, by securing a contact between the core and an end of a conductive elastic plate and a contact between the other end of the elastic plate and the inside face of the shielding case respectively.

CONSTITUTION: Supports 3 and 3 are molded with the insulating synthetic resin. A plate spring 7 is made of the phosphor bronze, etc. and conductive. The plate 7 has a basement 7a having a section folded into a chevron and a part 7b extending from the basement 7a toward a single side. A channel-shaped part 7c is folded downward at the tip part of the part 7b, and numbers of projections (b) are formed on the inner circumference surface of the part 7c. Such spring 7 is put on the upper surface of the support 3, and the part 7c is fitted to the outer circumference of cores 1 and 1 which are set to face the supports 3 and 3 from their tips to outer sides. Under such conditions, the whole structure is fitted into a shielding case 5.