To improve the machining accuracy as well as to realize a simple structure and low cost, and furthermore reduce the stepup adjusting time and the truing time.

In this centerless grinder, a blade is provided between a grinding wheel 4 and a regulating wheel 5, and a work supported on the blade is ground by giving a step by the grinding wheel 4 rotating at a high speed, while rotating the work by the regulating wheel 5. To the regulating wheel 5, a rubber grinding wheel with a high friction coefficient is used at the braking side, while a cast iron with a large abrasion-proof property and a low friction coefficient is used to the sliding side. This regulating wheel 5 is to be driven to rotate the braking side and the sliding side integrally.