A resonator element includes a substrate having 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. Excitation electrodes 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 μm