An electrostatic motor technology that makes it possible to actuate machines with normal dimensions (not micro machines) by electrostatic force is developed. The novel motor is named AC Dual Excitation Multiphase Electrostatic Drive (ADEMED). It consists of a pair of two thin plastic films, called slider and stator, in both of which 3-phase parallel electrodes are embedded. By applying a 3-phase AC voltage to the electrodes in the two films, the slider film slides on the surface of the stator. A prototype of the motor is fabricated and tested. The prototype has a mass of 7 [g] and generates a thrust force and a power of 4.4 [N] and 1.6 [W] respectively. From these measured power and mass, the power/mass ratio of this motor is calculated as 230 [W/kg]. In terms of this performance, this motor exceeds the standard of typical mechatoronic servo motors reaching the highest level of AC servo motors that are commercially available.