A miniaturized Electrical Discharge Machine (EDM) device based on ultrasonic motor has been developed to machine micro-holes in narrow space. In this mechanism, the electrode is driven without need of electrode holder, so that the mass and inertia of slider are greatly smaller, and feeding frequency of electrode can be raised compared to the conventional miniaturized EDM devices. This is a significant improvement that the electrode’s driving means varies from plane driving to line driving. Because of its advantage of compact size, the miniaturized EDM device can be fixed on robot. Differential Reciprocating Driving Method (DRDM) for EDM electrode is proposed. Feeding resolution of electrode reaches 0.5μm in stepping style, while resolution reaches 40nm in differential reciprocating style, and all above characteristics create preconditions for micro EDM machining. The holes with figures of Φ90μm inclined circle and inclined Y have been machined.