Sensor element and angular velocity sensor

A sensor element comprising:

• a piezoelectric body of a single crystal, comprising
• a base part, and
• a driving arm and a detecting arm which extend from the base part in a y-axis direction in an orthogonal coordinate system xyz,
• a plurality of excitation electrodes located on the driving arm in an arrangement enabling vibration of the driving arm in an x-axis direction, and
• a plurality of detecting electrodes located on the detecting arm in an arrangement enabling detection of a signal generated due to bending deformation in a z-axis direction of the detecting arm, wherein
• the piezoelectric body has anisotropy relative to a crystal orientation, the anisotropy making the driving arm cause vibration of torsional deformation when the driving arm vibrates in the x-axis direction,
• an orientation of the torsional deformation when the driving arm bends to a +x side is an orientation making the base part flex so that a connection position in the base part with the detecting arm is displaced to a one side in the z-axis direction, and
• a shape of a cross-section of the driving arm perpendicular to the y-axis direction is a shape where a bending stiffness to the +x side and to an other side in the z-axis direction is smaller than a bending stiffness to the +x side and to the one side in the z-axis direction.