A method to form a thick layer by screen printing and a method to form a piezoelectric actuator of an inkjet head. The method to form the thick layer including forming a guide groove in a surface to a predetermined depth, and forming the thick layer by applying a material to the surface inside the guide groove through screen printing. The method to form the piezoelectric actuator including forming an insulating layer on a top surface of a vibration plate and forming a guide groove in the top surface of the vibration plate or an insulating layer to a predetermined depth at a position corresponding to each of a plurality of pressure chambers, forming a lower electrode on the top surface of the insulating layer; forming a piezoelectric layer inside the guide groove by screen printing, and forming an upper electrode on a top surface of the piezoelectric layer.