Abstract: An ultra-precision grinding machine for finishing the work portion of the workpiece very accurately is disclosed, in which a Y-table which can freely move in the Y-axis direction is mounted on an X table which can freely move in the X-axis direction on a base plate, and a slide table for supporting the workpiece is mounted on this Y table so that it can freely move in any horizontal directions and freely revolve. The grinding tool adapted to be engagement with the work portion of the workpiece is supported to a machining head apparatus disposed upward of the slide table so that it can move vertically and freely micro-vibrate horizontally, and at the same time, the amplitude of the microvibration can be freely adjusted.