Proposed is an actuator using a bi-directional electrostatic force, which generates a bi-directional electrostatic force in order to amplify and vibrate the vibration of a vibrator. The actuator may include an upper electrostatic force generator configured to generate a first electrostatic force in response to a first high voltage signal, a lower electrostatic force generator configured to generate a second electrostatic force in response to a second high voltage signal having a phase difference with the first high voltage signal, and a vibration generator positioned in a space between the upper electrostatic force generator and the lower electrostatic force generator and configured to generate vibration in response to the first and second electrostatic forces.