A common electrode plate formed on a common electrode base attached to the lower surface of the movable stage faces a split electrode plate formed on a split electrode base attached to the upper surface of a main base, which are apart from each other at a predetermined interval. A support mechanism formed of ball bearings, ball stoppers at the movable side, steel balls, ball stoppers at the fixed side, and ball bearings allows the movable stage to move in directions of the X-axis, Y-axis and turning. A linear actuator 19 is driven to move the movable stage in the directions of X-axis, Y-axis, and turning.