To provide a means capable of preventing pressure leakage by efficiently mending the minute casting defect generated in the rim of the vehicle wheel without performing correction working or without exerting a significant burden on the work thereof.

There is provided the jig 1 for working the surface layer having a bottom plate member 62, a perforated wall member 61 disposed in a circumference form at the bottom plate member 62, a mounting member 71 for positioning and fixing the vehicle wheel 22 with respect to the perforated wall member 61, and a working material 25 housed in a slot 65 provided in the perforated wall member 61.