An inkjet head (10) includes a displacement film (17), a substrate (11), and an ink discharge portion (21). The displacement film (17) includes a piezoelectric thin film (14) as a driving film operable to expand and contract in a direction perpendicular to its thickness direction to cause curving deformation of the displacement film (17) in its thickness direction. The substrate (11) has a dug portion (11a) as a hole portion formed in its thickness direction, and supports the displacement film (17) such that the displacement film (17) covers the dug portion (11a). The ink discharge portion (21) has an ink chamber (21a) holding ink, and discharges the ink outside with pressure applied to the ink by the curving deformation of the displacement film (17). The ink discharge portion (21) is provided opposite to the dug portion (11a) of the substrate (11) with respect to the displacement film (17).