Whirling is applied to machining of microscrews on thin wires. A micro whirling machine has been developed for this. In order to suppress the vibration of the workpiece, the wire is inserted in polyurethane tubes clamped on a metal bar. Frequency analyses have been conducted by loading impulse forces at the center of the wire. The dynamic response is improved with reducing the vibration in the clamping force by the developed clamping system. Thirty micrometers microgrooves have been machined on 0.3 mm diameter stainless steel wires with fine surface finish, with the developed machine tool.