PROBLEM TO BE SOLVED: To provide a rotary auxiliary tool applicable to a rotation object body of various diameters, and hardly slipping to the rotation object body.SOLUTION: A rotary auxiliary tool 1 comprises a first arm 21a having a first engaging surface 22a for engaging with a rotation object body, a second arm 21b connected to the upper end of the first arm 21a and having a second engaging surface 22b for engaging with the rotation object body, a first handle 23a connected to the lower end of the first arm 21a and having a first gripping surface 24a gripped by a user, a second handle 23b connected to the lower end of the second arm 21b and having a second gripping surface 24b gripped by the user and a belt 30 arranged along the first engaging surface 22a, the second engaging surface 22b, the first gripping surface 24a and the second gripping surface 24b. The first arm 21a and the second arm 21b rock in the direction of being pressed to the rotation object body via the belt 30 when gripping the first gripping surface 24a and the second gripping surface 24b.SELECTED DRAWING: Figure 1