An electrostatic actuator includes: a fixed driving electrode that is disposed on a silicon substrate; a movable driving electrode that is disposed so as to face the fixed driving electrode and approaches the fixed driving electrode with an electrostatic force generated between the movable driving electrode and the fixed driving electrode; and a pair of spacers that comes in contact with the movable driving electrode in an approaching state in which the fixed driving electrode and the movable driving electrode approach each other and forms a prescribed air gap between the fixed driving electrode and the movable driving electrode, wherein each of the spacers has a spacer electrode portion that comes in contact with the movable driving electrode via an insulator and has the same potential as one of the electrodes at least in the approaching state.