PURPOSE: To facilitate an easy change of the eliminating band of high frequency noises, by adhering a dielectric material between a conductor ring passing through a center conductor of a signal line and a pierced hole of a larger diameter than the conductor ring to form a capacitor and attaching the capacitor to a box storing an electronic device in a free loading/unloading way to vary the capacity of the capacitor.

CONSTITUTION: A dielectric materal 15 is adhered between a conductor ring 13 passing through a conter conductor 9 of a coaxial connector 1 and a pierced hole of a larger diameter than the ring 13. Thus a flat plate type capacitor 17 is obtained. The capacitor 17 is attached to a metallic case 3 forming an electronic device storing box by means of screws 23 in a free loading/unloading way. The capacity of the capacitor 17 is varied in response to the frequency band of high frequency noises produced by the electronic device. Thus a change is facilitated for the noise eliminating band of a high frequency noise eliminating filter. As a result, the noises produced from the electronic device can be completely deleted.