Patent ID: 8294338

Claim:
A piezoelectric resonator element composed of a Z-cut piezoelectric plate in which two main planes regulating thickness cross a Z axis, comprising: a resonating arm, of which one end side, in a longitudinal direction, is a free end in a non-fixed state; a base portion that fixes another end side, in the longitudinal direction, of the resonating arm; a first groove that is arranged on a main plane of the +Z plane side of the resonating arm, along the longitudinal direction, and has a bottom in a shape in which it is cut out from the main plane in the thickness direction; and a second groove that is arranged on a main plane of the −Z plane side of the resonating arm, along the longitudinal direction, and has a bottom in a shape in which it is cut out from the main plane in the thickness direction; wherein an end that is on the base portion side of the second grove groove and positioned on the main plane side of the −Z plane side is positioned between (i) an end that is on the base portion side of the first groove and positioned on the main plane side of the +Z plane side and (ii) the free end, and wherein the end at the base portion side of the first groove is positioned closer to the base portion than the end at the base portion side of the second groove, an end that is on the free end side of the second groove and positioned on the main plane side of the −Z plane side is positioned between (i) an end that is on the free end side of the first groove and positioned on the main plane side of the +Z plane side and (ii) the free end, and a region in which the first and second grooves are overlapped with each other as seen from the thickness direction is provided with a region in which the first and second grooves are overlapped with each other as seen from a longitudinal direction.