PURPOSE: To bend the pipe into desired curvature utilizing the outer surface of the round grooved plate, by employing plural round grooved plates of different radii and the motor driven worm mechanism.

CONSTITUTION: At first, a unit of bending plate 20, possessing the groove fittable to outer diameter of the pipe 3 and the round grooved plate of required bending radius, is set to the frame 14. Next, the pipe 3 is fitted to the bending plate 20 with the holding metal 9, and the right side of the pipe 3 is borne by the roller 10. Then, the position of the limit switch 25 is set to the point corresponding to the desired bending angle of the pipe 3. And the bending plate 20 is rotated together with the pipe 3 by the motor 22 through the worm mechanism 23, 24. Hereby, the pipe 3 is slid on the roller 10 and is bent along the curved outer surface of the round grooved plate of the bending plate 20. When the knock pin 26 fixed on the worm wheel 24 hits the lever 27 of the limit switch 25, the power supply is interrupted at once at the aim bending angle.