A dielectric resonator comprises electrodes formed on both the main surfaces of a dielectric substrate and a thin film multi-layer electrode of thin film conductor layers and thin film dielectric layers having fixed thickness alternately laminated which constitutes at least one of the electrodes, and is characterized in that by giving abrasive treatment or etching treatment to the external portion of the dielectric substrate and the external portion of the electrodes formed on both the main surfaces of the dielectric substrate the end portions of the electrode is made in an electrically open-circuited condition. In this way, a dielectric resonator making effective use of the characteristic of low loss of the thin film multi-layer electrode is presented.