Patent ID: 8633638

Claim:
A piezoelectric resonator element composed of a Z-cut piezoelectric plate in which two main planes regulate 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 first main 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 second main 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 groove and positioned on the second main plane side is positioned between (i) an end that is on the base portion side of the first groove and positioned on the first main plane side and (ii) the free end, 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, and the bottom of the first groove faces and partly overlaps the bottom of the second groove.