The piezoelectric actuator comprises: a plate-shaped piezoelectric body which has a portion polarized in a thickness direction of the piezoelectric body and a portion polarized in a direction oblique to the thickness direction; and a pair of electrodes which are disposed on opposite surfaces of the piezoelectric body facing each other in the thickness direction across the piezoelectric body, have plane-symmetrical portions and plane-asymmetrical portions in relation to the piezoelectric body, are used as polarization electrodes for polarizing the piezoelectric body so that the portion polarized in the thickness direction and the portion polarized in the direction oblique to the thickness direction are formed in the piezoelectric body, and are used as drive electrodes for inducing strain in the piezoelectric body.