An insertion body includes: a base arranged in the central axis a rotating body provided on an outer periphery of the base and rotatable around the central axis and a channel which includes a guide provided at the base such that the rotative force transmitting section is able to be guided between a first position in which the rotative force transmitting section in the longitudinal axis can be inclined from the central axis when the rotative force transmission unit is inserted from the outside to the inside and a second position in which the rotative force transmitting section in the longitudinal axis is parallel to the central axis and a rotative force can be transmitted to the rotating body from the rotative force transmitting section, and through which the rotative force transmission unit is inserted through the opening end and the guide.
