PURPOSE: To facilitate frequency adjustment, to prevent Q from being lowered and to selectively couple the prescribed number of dielectric poles out of adjacent composite dielectric poles with each other.

CONSTITUTION: Plural composite dielectric poles 10a, 10b and 10c are arranged by setting a plane formed by each composite dielectric pole almost flush and setting the dielectric pole on one side of two dielectric poles which constitute adjacent two composite dielectric poles in parallel with the one on the other side, and windows 30, 31 for magnetic coupling with directivity at a boundary part are provided. In this way, the frequency adjustment can be applied to all the resonators in the same direction, and also, the prescribed number of dielectric poles out of the dielectric poles which constitute the composite dielectric poles can be magnetically coupled selectively. Also, a large window for magnetic coupling can be arranged between the adjacent composite dielectric poles and two pairs of dielectric poles can be magnetically coupled firmly.