An ink jet head includes a chamber unit including a pressure chamber formed to hold ink, and a nozzle plate unit. The nozzle plate includes a vibrating plate forming a bottom wall of the pressure chamber, a driving element that is provided on a bottom surface of the vibrating plate and configured to cause a volume of the pressure chamber to be changed by deforming the vibrating plate upon application of voltage to the driving element, and a protective layer disposed on a bottom surface of the vibrating plate and a bottom surface of the driving element. The protective layer has a first thickness between a bottom surface thereof and the bottom surface of the vibrating plate and second thickness between a bottom surface thereof and the bottom surface of the driving element, and the first thickness is greater than the second thickness.