To safely attach/detach nuts and bolts for fitting a tire wheel and a wheel cover without damaging hole parts, notched parts and the periphery thereof.

An attachment/detachment tool 10 comprises a substantially cylindrical outer insertion body 11 with tip part insertable in a hole part 3, and an inner insertion body 12 in which a ring 14 can be attached to a substantially cylindrical groove part 13 formed on the outer circumferential part on the tip side rotatable around the axis 0 inside the outer insertion body 11. The outside diameter of the inner insertion body 12 in the part of the ring 14 is set to be larger than the inside diameter 1 and smaller than the inside diameter 2, the inner insertion body is slidable along the direction of the axis 0 and rotatable around the axis 0 in a range of the inside diameter 2. A fitting part 15 of a hexagonal hole shape which is fitted to a nut 4 to be screwed to a bolt of an axle is formed on a tip part of the inner insertion body 12. A prismatic rotating working part 17 of an impact wrench 16 is inserted in and engaged with a base end part of the inner insertion body 12 to form each hole-shaped engagement part 18.