A new centreless grinding technique was proposed for the process of microscale parts. Instead of using a regulating wheel, an ultrasonic vibrating regulator was employed to support the workpiece and control the rotational speed of the workpiece with the blade. The dimensions of the regulator were determined by FEM analysis. In order to confirm the motion of the end face of the regulator could be controlled by the parameters applying to the PZT, a measuring system was construed to measure the performance of the regulator. The rotation speed control test was used to confirm the workpiece rotation speed could be precisely controlled by the ultrasonic motion of the regulator. A regulator was installed on an existing centreless grinder to perform actual microscale centreless grinding operations involving a tungsten carbide workpiece 60 μm in diameter and 15 mm in length. The experimental result proves the validity of the new centreless grinding technique.