An electrostatic actuator is disclosed that includes a deformable oscillating plate that is deformed by electrostatic force, an electrode that is arranged opposite the oscillating plate via a gap formed by sacrificial layer etching, a connection path that is connected to the gap, an atmosphere connecting hole that connects the connection path to the exterior, and a resistance path arranged between the atmosphere connecting hole and the connection path. The resistance path is configured to resist penetration of a sealing agent for sealing the atmosphere connecting hole into the connection path.