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; and a first mass portion for adjusting a resonance frequency of the vibrating arm, wherein the vibrating arm performs flexural vibration in a direction perpendicular to the plane and has a first surface which contracts or expands with the flexural vibration and a second surface which expands when the first surface contracts and contracts when the first surface expands, and wherein the first mass portion is provided on at least one of the first and second surfaces and approximately at the center of the length of the vibrating arm from a base-side end to a tip end thereof.