A piezoelectric actuator includes one piezoelectric layer, a common electrode disposed on the lower surface of the piezoelectric layer and individual electrodes disposed on the upper surface of the piezoelectric layer. In the piezoelectric layer, a plurality of metal patterns arranged at regular intervals in the conveyance direction and in a direction orthogonal to the conveyance direction and overlapping with pressure chambers are provided substantially at the central part in the direction of the thickness. The metal patterns are not electrically continuous with each other and not electrically continuous with other parts. The metal patterns situated outermost in the conveyance direction are disposed so as to cross the edge of the pressure chamber. Some metal patterns overlap with the individual electrode and the other metal patterns do not overlap with the individual electrode.