<p>A device on a sewing machine for severing thread chains comprises a driven movable cutting knife which has a cutting edge disposed to move in a path in which it is spaced from a stationary counterknife. The driven knife is continuously rotated during the ordinary sewing operation, and when cutting is to be effected, the thread chain is directed so that it is moved over the counterknife to place it in a deflection position in the path of movement of the movable cutting knife and cause the movable cutting knife to move in a path in which it comes into the range of cooperative interengagement with the stationary counterknife.</p>
