Tuning-fork type quartz crystal vibrating element and piezoelectric device

A tuning-fork type quartz crystal vibrating element, comprising:

• a base part;
• a pair of vibration arm parts extended in a same longitudinal direction from the base part;
• and
• respective weight parts located at tips of the vibration arm parts, wherein
• provided that, on a plan view, a measurement in the longitudinal direction is defined as length, a measurement in a direction perpendicular to the longitudinal direction is defined as width, a reference value of the length of the vibration arm parts together with the respective weight parts is defined as x0, and a reference value of the width of the weight parts is defined as y0,
• following Expression (1) applies, where a difference between the length of the vibration arm parts together with the respective weight parts and the reference value x0 is x, a difference between the width of the weight parts and the reference value y0 is y, and a unit is μm:
• −100≤x≤100,
• −30≤y≤30, and
• −0.3x−15≤y≤−0.3x+15 (1).