To provide a piezoelectric actuator in which the voltage-amount of displacement characteristics can be measured with high accuracy in a short time.

A piezoelectric actuator 1 comprises a ceramic laminate 15 where a piezoelectric ceramic layer 16 and internal electrode layers 13, 14 are laminated alternately and formed into a rectangular parallelepiped having front and back surfaces 15A, 15D facing each other and side surfaces 15B, 15C facing each other, an external electrode 11 formed on the side surface 15C and the front and back surfaces 15A, 15D of the ceramic laminate 15, and an external electrode 19 formed on the side surface 15B and the back surface 15D of the ceramic laminate 15. On the back surface 15D of the ceramic laminate 15, a protective film 18 covering the external electrode 19, and a protective film non-forming part 17 which exposes both a part 11D of the external electrode 11 and a part 19D of the external electrode 19 are formed. On the surface 15A of the ceramic laminate 15, a protective film 12 covering the external electrode 11 is formed.