To provide a device wherein an entire rotation treating member including a grinding wheel and a shaft is easily changed without falling off of parts.

In a treating tool main body, a tip member 62 freely bendable at a hinge part 61 is provided on the tip side of a guiding tube 12, a rotation treating member 70 is inserted through an attaching hole 68 communicated with the guiding tube 12 side into the tip member 62 and its tip side is freely rotatable against the tip member 62 via bearings 71 and 72 having a flange part 78. In the tip member 62, a pulling out preventing groove 81 orthogonal to the axial direction of a shaft part 75 and intersecting the attaching hole 68 is formed in a tip side adjacent to the bearing 72 and a pulling out stopper 82 is housed therein and retained by the energization of a leaf spring so as to prevent the movement of the bearing 72 side in the axial direction. This coming-off stopper 82 is supported by a pulling out preventing shaft so as to be rotatable in the coming-off preventing groove 81 and the rotation treating member 70 is inserted/pulled out by rotating the coming-off stopper 82 so as to release the engagement.