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, an individual electrode facing the diaphragm with a gap therebetween, while a voltage is applied between the diaphragm and the individual electrode, and an insulating film which is disposed on a surface of the diaphragm, the surface facing the individual electrode, are included, wherein the insulating film is converted to an electret.