To shorten a whole length and to reduce an installation space by vertically arranging each device in the bending device.

By operating a chuck arm 25 for opening/closing, the outer periphery of a work is held by a chuck claw 23. By running a vertical self running device 30b, a bending point of the work is positioned at the right side of center of a bending die 17. By operating a bending device slide actuator 13, a bending device 10 is positioned. The outer periphery of work is fitted in the groove part of bending die 17. A mandrel 41 is inserted in the hollow part of work, further, moved to the position of bending point. A clamp die 16 is abutted on the work so as to be protruded. By operating a pressure actuator 19, a pressure die is abutted on the work and pressed to the bending die 17. By following the pressure die to turning of the bending die 17 and clamp die, the work is bent.