Abstract: A resonator element includes: a substrate which includes a first region performing thickness shear vibration, a second region located in a periphery of the first region and having a smaller thickness than the first region, a fixed end, and a free end opposite to the fixed end in the first region in a plan view; and excitation electrodes which are disposed on a front and a rear of the first region and have regions overlapping each other in the plan view. A center of the first region and a center of the regions overlapping each other are located between a center of the substrate and the free end in the plan view. When Cs is a distance between the center of the regions overlapping each other and the center of the substrate in the plan view, a relation of 105 ?m<Cs<130 ?m is satisfied.

Abstract: A resonating element has a quartz crystal substrate having a vibrating portion and a thin-walled portion that is thinner than the vibrating portion, and a pair of excitation electrodes respectively disposed on opposite surfaces of the vibrating portion. Moreover, in the excitation electrode, each of a pair of sides arranged in a Z?-axis direction is convexly curved toward the center so that the excitation electrode has a constricted portion in which a length in the Z?-axis direction increases gradually from a central portion toward both ends in an X-axis direction.