Abstract: Die opening-closing means 10 includes a servo motor 11 and a movement conversion mechanism and is disposed between a support plate 8 and a base stand 1. A movable plate 4 is mounted on the support plate 8 that is disposed on the base stand 1 via a linear movement guide 7. In a forging cycle, die opening and closing is performed by activation of the die opening-closing means 10 and tie bar fixing means 21 at a rear surface side of the movable plate 4, and clamping force is obtained using a die clamping cylinder 30 provided in the movable plate 2. When it is necessary to change over exclusive dies 3b and 5b, change over is performed by: extending tie bar removal cylinders 41 provided in a frame 40 behind the movable plate 4 so as to remove tie bars 6 from a fixed plate 2; and moving a movable rail 52b of internal rails 52 to an open position and moving the change over carriage in along the internal rails 52 from the outside.