Abstract: A tuning fork quartz crystal resonator includes a base, a first resonating arm, and a second resonating arm. The base has a generally planar fifth main surface and a generally planar sixth main surface opposite to each other, and has a fifth side surface and a sixth side surface opposite to each other. The first resonating arm is connecting to one side of the base. The second resonating arm is connecting to the same side of the base. A concave of continuous curved surface is formed one each on the fifth side surface and the sixth side surface of the base respectively.

Abstract: A tuning fork quartz crystal resonator includes a base, a first resonating arm, and a second resonating arm. The base has a generally planar fifth main surface and a generally planar sixth main surface opposite to each other, and has a fifth side surface and a sixth side surface opposite to each other. The first resonating arm is connecting to one side of the base. The second resonating arm is connecting to the same side of the base. A recess is formed on the fifth main surface, and the recess is sized and configured such that a first width near the first resonating arm and the second resonating arm is greater than a second width away from the first resonating arm and the second resonating arm.