A high-frequency device comprises a dielectric substrate, a filter element which has a plurality of resonating elements made of a first superconductor film on the dielectric substrate, a dielectric plate which faces the dielectric substrate substantially in parallel with the substrate and covers the plurality of resonating elements, and a spacing adjusting member configured to control the spacing between the dielectric plate and the dielectric substrate. The high-frequency device enables the pass-band frequency of the filter to be adjusted with high accuracy without variations in the skirt characteristic or ripple characteristic.