A resonator element includes: a base portion provided on a plane including a first axis and a second axis orthogonal to the first axis; a vibrating arm extending from the base portion in the first axis direction; an excitation electrode provided on the vibrating arm so as to excite the vibrating arm; and a first mass portion provided on the vibrating arm so as to adjust the frequency of the vibrating arm, wherein the vibrating arm performs flexural vibration in a direction perpendicular to the plane and wherein the first mass portion is provided in a region exceeding ½ of the entire length in the first axis direction of the vibrating arm from the end of the vibrating arm close to the base portion and is formed from a material whose density D (in units of 103 kg/m3) is in the range of 2.20≦D≦8.92.