A piezoelectric actuator 1 capable of being driven with a high electric field intensity, obtaining a larger displacement and being high in electric conducting reliability of electrodes, and comprising: at least one cell 3 defined by two side walls 6, a substrate 2 and a ceiling wall 7; the two side walls being disposed on the substrate and being covered with the ceiling wall to define one cell, at least the two side walls 6 comprising piezoelectric/electrostrictive devices 4, and the piezoelectric/electrostrictive devices 4 being capable of changing a volume of the cell 3 by displacement of the walls. Each of the piezoelectric/electrostrictive devices 4 comprises a plurality of layered piezoelectric/electrostrictive bodies 14 and electrodes 18, 19 which are alternately stacked, and end portions of the electrodes 18, 19 are embedded in the piezoelectric/electrostrictive bodies 14 in at least the internal side of the cell 3.