To provide a dielectric waveguide resonator and a filter which are easily designed and manufactured independently of the frequencies of signals.

A cutoff waveguide (d) is provided to a part of a dielectric waveguide 1 which is formed in a dielectric board and provided with an H plane composed of conductor layers 1a and 1b, and an E plane composed of a group of conductor vias 1c arranged at an internal below half the wavelength of signals or a group of conductor vias 1c and a conductor belt 1d. Dielectric vias 5 which are formed of dielectric which has higher dielectric constant than that forms the dielectric waveguide are provided in the cutoff waveguide d.