If processing speed is increased and processing time is lengthened, a magnetic abrasive system can be used as a tool both for finishing and precise dimensional control of manufactured products at the micro-level, and for mirror face processing. Tn this study, a micro machining system that can change its high rotational speed was developed. Using micro machining with a high speed magnetic abrasive system, the diameter of difficult-to-cut materials with high hardness could be controlled almost linearly by changing the rotational speed, the frequency of magnetic poles, and the size of diamond particles. By changing machining conditions, the surface roughness of the mirror face level could be obtained. To improve roundness, a higher rotational speed improved processing time and dimensional precision, and 20,000 rpm was the optimum speed in this experiment. Roundness was obtained up to $0.15;{mu}m$. Before and after the processing, there was almost no change in the WC(tungsten carbide) and Ni components of the material, and there were no remains of mixed-type particles such as iron and diamond on the material.