An ink jet head includes an insulating base (10), a plurality of parallely arranged multilayer piezoelectric elements (20) each of which is formed by alternately stacking a conductive material and a sheet-like piezoelectric material polarized in the direction of the thickness and the lowermost and uppermost layers (25, 26) of which are non-driven layers which do not deform even when voltages are applied thereto, an oscillation plate (30) deflectable flexibly, and a flow passage plate (40) equipped with a plurality of ink outlets (43) at the front thereof and having a plurality of ink chambers (41) arranged in a line and communicating with these ink outlets (43). The lowermost layers (25) are bonded to the upper surface of the base (10), and the oscillation plate (30) is bonded to the upper surfaces of the uppermost layers (26), and the flow passage plate (40) is bonded to the upper surface of the oscillation plate (30). The ink chambers (41) are disposed in the direction of displacement of the multilayer piezoelectric elements (20). A front member (50) is bonded to the front surface of the piezoelectric elements (20) and to the front portion of the oscillation plate (30).