Flexural mode resonator element, resonating device, and electronic apparatus

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×W1≦L≦6×W1 where L is the length of the reduced cross-section portion in the extending direction of the vibration arm, and W1 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.