To provide a mounting structure of an emery wheel capable of attempting simplification mounting work of the emery wheel and its corresponding automation by eliminating bolt fastening at a plurality of points conventionally required in mounting the emery wheel on a wheel spindle and a grinder furnished with it.

This structure to mount the emery wheel 32 on the wheel spindle 31 by pressure-welding it on a wheel stopper 34 is furnished with a positioning means 4 having a first positioning part 4A to position the emery wheel 32 in the circumferential direction on the wheel spindle 31 and a second positioning part 4B to position the emery wheel 32 in the axial direction on the wheel spindle 31. Consequently, it is possible to certainly prevent occurrence of slippage in the rotating direction and in the axial direction of the emery wheel 32 due to grinding resistance, etc.