To provide an electrostatic actuator capable of attaining a large diaphragm displacement by low voltage drive. Furthermore, a droplet discharge head provided with this electrostatic actuator, a method for driving a droplet discharge head, and a method for manufacturing an electrostatic actuator are provided. A diaphragm 4, an individual electrode 11 facing the diaphragm 4 with a gap 10 therebetween, while a voltage is applied between the diaphragm 4 and the individual electrode 11, and an insulating film 4a which is disposed on a surface of the diaphragm 4, the surface facing the individual electrode 11, are included, wherein the insulating film 4a is converted to an electret.