A method of manufacture an ink jet head in which an ink is jetted from a nozzle hole by applying an electric voltage to an electrode so as to deform ink chambers divided by a partition wall. The method includes the steps of providing plural piezoelectric base plates having polarization side by side on a first non-piezoelectric plate, forming plural grooves for the ink chambers on the piezoelectric base plates and at connecting portions where each edge of the plural piezoelectric base plates provided side by side comes to face other edge; and mounting a second non-piezoelectric base plate on the plural piezoelectric base plates as so to cover the plural grooves so that the ink chambers divided by the partition wall are formed.