To lower a frequency by simple constitution by providing a through-hole inside a dielectric block, forming electrodes by baking silver paste to the outer and inner peripheries of the dielectric block and providing the frequency adjustment part of conductive metal on an inner peripheral electrode.

The prismatic dielectric block 2 of dielectric ceramic is provided with the through-hole 1 from one end face to the other end face. Also, an outer peripheral electrode 3 is provided on the outer peripheral side face of the dielectric block 2 and the inner peripheral electrode 4 is provided on the inner peripheral surface of the through-hole 1. In this case, the outer peripheral electrode 3 and the inner peripheral electrode 4 are formed by baking the silver paste to the dielectric block 2. Also, open end faces 2a and 2b are turned to the end faces for which the electrode of the surface in contact with the through-hole 1 of the dielectric block 2 is eliminated and the dielectric block 2 is exposed. The frequency adjustment part 6 constituted of the conductive metal is connected to one end part 4a of the inner peripheral electrode 4 by a conductive adhesive material and projected outwards from the open end face 2a. Also, the other end part 2b is turned to an input/output end part used for connection with an external circuit. By such simple constitution, the frequency is lowered.