The high removal rate ultra-smoothness grinding method which can finish to almost the same smoothness formed by polishing has been recently desired strongly for high efficiency production of high quality components. In the report, the existing of limiting smoothness, which can be attained in traverse grinding is discussed theoretically and presented experimentally. On the basis, the newly devised ultra-smoothness grinding method is proposed and ascertained to be useful for finishing to near the ultra-smoothness surface. In the new method, first of all, the workpiece-wheel contact width is ground by feeding toward the direction normal to grinding direction (wheel revolution direction). Next after the workpiece is slightly step-fed to the direction parallel to grinding direction so that the geometrical surface roughness formed by overlapping the cross-section of two wheel circles before and after the step-feed is lower than the required surface roughness, the workpiece-wheel contact width is ground again by feeding reversely toward the direction normal to grinding direction. The whole surface of workpiece is finished by repeating such a grinding process. The surface roughness of cemented carbide tool formed by the ultra-smoothness grinding method using the #140 diamond wheel is found to attain below 30nm(Rz) or 5nm(Ra).