In a chip-type piezoelectric-resonator, which is protected with thermosetting resin, mother sheets are bonded to cover both major surfaces of a mother substrate having a plurality of piezoelectric resonance elements which are provided on a piezoelectric substrate, in order to properly form vibrating spaces. The mother sheets are provided with concave portions for defining cavities for vibration. Then, protective resin is applied to cover the mother substrate which is bonded with the mother sheets, and thereafter the mother substrate is divided so as to obtain a plurality of chip-type piezoelectric-resonators.