A resonator element capable of improving impact resistance is provided. A quartz crystal resonator element is a resonator element formed by etching a Z plate which is cut at predetermined angles with respect to the crystal axes of a quartz crystal. The quartz crystal resonator element includes a base, a pair of resonating arms extending from the base in the Y-axis direction, and a positive X-axis notch and a negative X-axis notch formed by notching the base in the X-axis direction. The positive X-axis notch is formed by notching the base from the negative side of the X axis towards the positive side so that the width of the positive X-axis notch increases as it approaches the outer circumference.