A conductive film is provided on a dielectric substrate. The conductive film has conductor opening portions, which serve as inductive regions, and a conductor opening portion, which serves as a capacitive region. Multi-step ring resonator elements, each including a conductor line aggregate, are provided on respective substrates to configure resonator elements. The resonator elements are mounted above the conductor opening portions that serve as the inductive regions. This arrangement provides a resonator having a high Qo.