In a dielectric block having a through-hole, an outer surface electrode is formed on the outer surface of the dielectric block excluding the outer surfaces having the openings of the through-hole, and an inner surface electrode is formed on the inner surface of the through-hole. The dielectric block is made of a dielectric of which the dielectric constant having a negative temperature coefficient, that is, the dielectric constant increases as the temperature decreases. The inner surface electrode is formed by lamination of a superconductor film and a metallic film, and similarly, the outer surface electrode is formed by lamination of a superconductor film and a metallic film.