Patent ID: 8299863

Claim:
A flexural mode resonator element comprising: a vibration arm extending from a base end toward a tip; a base joined to the vibration arm at the base end; and supporting arms arranged on both sides of the base in a width direction perpendicular to an extending direction of the vibration arm and joined to the base, wherein the base has a reduced cross-section portion disposed along the extending direction of the vibration arm between a joint portion with the vibration arm and a joint portion with the supporting arms, and the reduced cross-section portion is disposed so as to satisfy a relationship 2×W 1 ≦L≦6×W 1 where L is the length of the reduced cross-section portion in the extending direction of the vibration arm, and W 1 is the arm width of the vibration arm; wherein the reduced cross-section portion is disposed by forming notches along both side portions of the base between the joint portion with the vibration arm and the joint portion with the supporting arms.