A piezoelectric actuator that includes a multilayer body, a low-potential outer electrode, and a high-potential outer electrode. The multilayer body includes multiple alternately stacked piezoelectric ceramic layers and planar electrodes. The planar electrodes include low-potential planar electrodes electrically connected to the low-potential outer electrode and high-potential planar electrodes electrically connected to the high-potential outer electrode. The planar electrode positioned most outwardly on the side of a first main surface of the multilayer body is a low-potential planar electrode. The inner surface of this low-potential planar electrode contacts the − side of polarization in an active region, and the outer surface of this low-potential planar electrode is exposed on an outside of the multilayer body. On the side of a second main surface of the multilayer body, a high-potential planar electrode is not exposed on the outside of the multilayer body.