A compact dielectric resonator device that permits reduction in size of a metal cover without deterioration of the filter characteristics of the device. As a result, even if the relative pressure of the water vapor in the atmosphere is less than 1. Decoding paths that correspond to decoded data bits that are inconsistent with the a-priori bit values may be removed from the possible decoding paths to consider, and decoding the encoded data bits by selecting a decoding path from remaining decoding paths of the possible decoding paths that were not removed. The actuating member is secured on the operating member so as to be co-rotatable therewith.