In the use of carbon-fiber reinforced plastics it is often necessary to cut the components, but the cutting of CFRP is usually made difficult by delamination of the composites and by a short tool life. In this paper, the machinability of CFRP by means of ultrasonic-vibration cutting is investigated experimentally. The experimental results have led to the trial application of ultrasonic-vibration cutting, which has been verified to be highly effective in terms of cutting force and surface quality.