An electrostatic ink jet head (1) using an electrostatic actuator and its manufacturing method, comprising pressure chambers (6) communicating with ink nozzles (21) and an atmospheric pressure chamber (12) open to the atmosphere, wherein diaphragms (5) are formed on the bottom surfaces of the pressure chambers (6), a voltage is applied between the diaphragms (5) and electrodes (43) to vibrate the diaphragms (5) electrostatically so as to inject ink droplets, vibration chambers (41) communicate with a pressure compensating chamber (49), a displacement plate (16) which is displaceable toward the outside of the bottom surface of the pressure compensating chamber (49) according to a variation in atmospheric pressure is formed on the bottom surface of the pressure compensating chamber (49), the volume of the pressure compensating chamber (49) is increased or decreased according to the displacement of the displacement plate (16) so that the inside pressure of each vibration chamber (41) communicating with the pressure compensating chamber (49) is regulated to the atmospheric pressure, whereby the vibration characteristics of the diaphragms (5) can be kept constant even if the atmospheric pressure is varied so as to maintain an appropriate ink-droplet injecting operation.