High-performance piezoelectric device with piezoelectric element

A piezoelectric element comprising:

• a piezoelectric body having a first surface and a second surface, wherein the second surface is different from the first surface;
• a first electrode provided at the first surface;
• and
• a second electrode provided at the second surface, wherein
• the piezoelectric body contains a polylactic acid crystal,
• the polylactic acid crystal has a helical structure and has a unit cell having an a axis, a b axis, and a c axis as crystal axes,
• lengths of the crystal axes satisfy a relationship of b axis<a axis<c axis,
• the c axis is parallel to an advance axis of the helical structure, and
• an orientation axis is the b axis,
• the orientation axis is uniaxially oriented in a manner of intersecting both the first surface and the second surface, and
• a degree of orientation of the orientation axis in the piezoelectric body is 0.80 or more.