PURPOSE: To so arrange the device that forgings are forged under alternating forging forces of several tens to several hundreds Hz and the need for corner projecting and hardie processes is eliminated by mounting a vertical fluid pressure cylinder to the cross head which elevates the screw column fixed to a bed frame provided with a lower anvil, and doing others.

CONSTITUTION: A cross head 1 provided with slide guides 2 and a bed frame 3 are connected to a screw column 4. A motor 6 is driven to rotate rotary nuts 5 and elevate the cross head 1. A fluid pressure cylinder 7 whose axial line is perpendicular is mounted so as to pass appoximately the central part of the cross head 1. A slide 9 is mounted to the bottom end of the rod 8 of the cylinder 7. An upper anvil 11 is disposed to the bottom face of the slide 9 and a lower anvil 12 to the top face of the bed frame 3 respectively. The pressure oil from a hydraulic pressure source 20 is controlled of the oil quantity by a servo valve 19 and is sent to the cylinder 7 which in turn lowers the rod 8. Thereby, the forging 13 is forged by both anvils 11, 12.