A piezoelectric device including: a substrate; a first conductive layer formed over the substrate, the first conductive layer including a conductive oxide layer formed of a (001) preferentially oriented lanthanum nickelate, and the lanthanum nickelate having oxygen deficiency; a piezoelectric layer formed over the first conductive layer and including a piezoelectric having a perovskite structure; and a second conductive layer electrically connected with the piezoelectric layer.