PURPOSE: To surely move a carrying belt by small tension by moving one clamp means for clamping the carrying belt, by a clamp moving means.

CONSTITUTION: Clamp cylinders 10a, 10b are moved to an initial position in the carrying direction, respectively, and a carrying belt 8 is clamped integrally by one clamp cylinder 10a. Subsequently, the clamp cylinder 10a is moved in the carrying direction of a part 1 to be formed by a moving cylinder 13, and the carrying belt 8 is fed by a stroke portion of the moving cylinder 13. In this state, before the clamp cylinder 10a reaches a moving final point, the carry ing belt 8 is released, and this time, the carrying belt 8 is clamped by the other clamp cylinder 10b and a feeding operation of the carrying belt 8 is executed continuously by the moving cylinder 13. In the course of the feeding operation of the carrying belt 8 by this clamp cylinder 10b, the clamp cylinder 10a is returned to its initial position, and continuously from the clamp cylinder 10b, the clamp cylinder 10a executes the feeding operation of the carrying belt 8 once again.