The present invention provides a piezoelectric actuator with excellent durability. In the present invention, a piezoelectric element 2 in which a plurality of piezoelectric layers that expand in accordance with an applied voltage, and internal electrode layers for supplying an applied voltage, are alternately laminated, and at least a part of the side surfaces 201 and 202 thereof is covered by an external packaging resin 25, the piezoelectric element 2 being housed in a sealed container 11 that substantially isolates it from the external atmosphere, and in which the internal atmosphere 19 is replaced by an inert gas. Alternatively, the piezoelectric element 2 is housed in a sealed container 11 that substantially isolates it from the external atmosphere, and the external packaging resin 25 includes an antioxidant.