To provide a dielectric resonator which reduces deviation between a resonant frequency of the dielectric resonator in a temperature for use and a resonant frequency of the dielectric resonator in a room temperature of 295K.

In a dielectric resonator (10) provided with a dielectric substrate 11 and a superconductive electrode 14 composed of a superconductive layer 12 and a metal layer 13 formed on both principal surfaces of the dielectric substrate 11, when the average thickness of the superconductive layer 12 is defined as d(μm), the temperature for using the dielectric resonator 10 lower than a transition temperature of a superconductor comprising the superconductive layer is defined as T(K), the resonant frequency of the dielectric resonator 10 in the temperature T for use is defined as ft(MHz) and a temperature coefficient of the resonant frequency of a dielectric comprising the dielectric substrate 11 is defined as τf(ppm/K), a relation of |d-2{τf×ft×(295-T)×10-6}|≤6 (d>0) is satisfied.