To reduce the trouble and labor of an operator by simplifying positioning and installation work of a rotating device of a wheel assembly.

A support device 6 that supports a wheel assembly 5 is structured to be movable in such a direction that the support approaches and separates to/from a rotating device by a traveling body 27 together with a lifting device. The lifting device is provided with a tilting arm 11, and an angle θ of the tilting arm 11 to the horizontal when the free end part 8 of the tilting arm 11 is abutted on around a top portion 7 of a tire 3 is detected by a tilting angle detection device 14. A height H1 from the support device to a proximal portion 9 of the tilting arm 11 is detected by a height distance detection device 15. The wheel assembly 5 is lifted up by a height distance H2 up to an axial line L2 of a chuck device by the lifting device.