A dielectric resonator block has at least three resonators and coupling device for coupling the adjacent resonators. A reactance element is added in parallel to the coupling device to provide an attenuation pole. A capacitor block of a dielectric material is provided which has through-holes to form hole electrodes and a surface electrode so that two coupling capacitances are provided. One of the two coupling capacitances serves as the reactance element. One of the hole electrodes of the capacitor block is connected with an external connector, and the other hole electrodes are connected with the resonators.