This report aims to investigate experimentally the possibility of ductile-mode ultra-smoothness grinding of fine ceramics using a coarse grain size diamond wheel. According to previous experiments, the results obtained in the ductile-mode surface plunge grinding of fine ceramics using a coarse grain size diamond wheel, showed that grinding groove heights over 200nm(Ry) were formed on the workpiece surface by the cutting edges. To diminish the groove heights, in the research, the grinding groove height diminishing-method in which cross-feeding the workpiece at high speed normal to grinding direction is done together with simultaneously feeding at a extremely slow speed parallel to grinding direction, is devised and the availability of the method is examined by surface grinding experiments. The fine ceramic used is the hot pressed silicon carbide. The grinding wheel is the metal bond diamond wheel of the grain size of mesh #140 and the concentration of 50. The ground workpiece surface is observed with differencial interference microscope and SEM, and its roughness is measured with a interferometric surface profiler and AFM. Using this diminishing-method, the grinding groove height diminishes considerably and the surface smoothness below 10nm(Ry) or 2nm(Ra) is attained.