The present invention has an object to provide a small, light-weight, impact-resistant, high-accuracy, and low-cost piezoelectric actuator which can achieve a large displacement at a low drive voltage as well as an information storage device which incorporates the piezoelectric actuator and has high recording density. The piezoelectric actuator according to the present invention is equipped with a hinge plate 220 which has a central portion 221, two lateral portions 222 extending point-symmetrically from both ends of the central portion 221, and two limbs 223 extending point-symmetrically and non-linear symmetrically from both ends of the central portion 221 as well as with a piezoelectric element 210 which brings the two limbs 223 toward and away from each other.