PURPOSE: To perform bending of different radius of curvature quickly by connecting the first and second supporting arms by a connecting device and thereby rotating the second arm and bending roller in a body with the first arm.

CONSTITUTION: The first and second supporting arms 51, 52 rotates in a body around a shaft 56 by transmission of driving force to a gear 58 from a driving power source. A bending roller 20 on the second supporting arm also rotates around the shaft 56 and bends a pipe 16 with the center roller 18 through a die 76. Bending of different radius of curvature is made possible by changing the center roller 18 and moving the bending roller 20 in the direction of radius along an opening 66.