Piezoelectric vibrating piece and piezoelectric device

A piezoelectric vibrating piece, comprising:

• a piezoelectric substrate, formed in a flat plate shape and vibrated in a thickness-shear vibration;
• a first excitation electrode, formed on one principal surface of the piezoelectric substrate;
• and
• a second excitation electrode, formed on another principal surface of the piezoelectric substrate, wherein
• the first excitation electrode is formed to have an identical thickness as a whole,
• the second excitation electrode includes a main thickness portion and an inclined portion, the main thickness portion is formed to have a constant thickness, the inclined portion is formed on a peripheral area of the main thickness portion, the inclined portion is formed to gradually decrease in thickness from a part contacting the main thickness portion toward an outermost periphery of the second excitation electrode,
• the main thickness portion is formed to be thicker than a thickness of the first excitation electrode, and
• the inclined portion has a width as an inclination width formed in a length of 0.84 times or more and 1.37 times or less of a first flexural wavelength and 2.29 times or more and 3.71 times or less of a second flexural wavelength,
• wherein the first flexural wavelength is a wavelength of a flexure vibration at a fundamental wave of the thickness-shear vibration, the second flexural wavelength is a wavelength of a flexure vibration at a third harmonic of the thickness-shear vibration.