Lead screws (56a to 56d) and nut members (62a to 62d) screwed to the respective lead screws (56a to 56d) are provided on a wire operation section (52) for operating wires (14) for operating a bending section (10) in a bending manner, and a driving force generating means (19), a drive coupling shaft (37) rotationally driven in a spin direction by a driving force from the driving force generating means (19), and drive couplings (31a to 31d) are provided on a drive source unit (8B) separably coupled to the wire operation section (52). The lead screws (56a to 56d) are rotationally driven in a spin direction from the driving force generating means (19) via the drive coupling shaft (37) to move the nut members (62a to 62d) in the axial direction thereby performing pulling operation of the wires (14) during coupling of the drive source unit (8B) and the wire operation section (52).
