PIEZOELECTRIC VIBRATING REED AND PIEZOELECTRIC VIBRATOR

PROBLEM TO BE SOLVED: To provide a piezoelectric vibrating reed having a multilevel mesa structure which can reduce a CI value.SOLUTION: The piezoelectric vibrating reed includes: a piezoelectric substrate 10 comprising an AT-cut quartz substrate and having a thickness direction parallel to a Y' axis; and excitation electrodes 20 arranged in obverse-reverse opposition in vibrating regions on both principal surfaces of the piezoelectric substrate 10. The piezoelectric substrate 10 has a rectangular excitation portion 14 having longer sides parallel to an X axis and shorter sides parallel to a Z' axis, and a peripheral portion 12 having a smaller thickness than the excitation portion 14 and formed around the excitation portion 14. The excitation portion 14 has a first portion 15, and a second portion 16 having a smaller thickness than the first portion 15 and formed around the first portion 15. Relationships 8≤Z/t≤11 and 0.6≤Mz/Z≤0.8 are satisfied, where Z is a dimension of the piezoelectric substrate 10 parallel to the Z' axis, Mz is a dimension of the shorter sides of the excitation portion 14, and t is the thickness of the first portion 15.