PURPOSE: To make the spontaneous action of a polishing layer at a polishing work time excellent and to polish a ceramic material continuously with a high polishing efficiency by bonding an aluminum nitride nitride powder as the abrasive grain whose mean grain size is 0.5μm to 1.5μm by a binder consisting of the liquid or resin whose binding force is low.

CONSTITUTION: An aluminum powder is effective as a ceramic polishing abrasive grain easy to cause degranulation especially and the grain size is adequately selected in the grain size range in 0.5μm to 1.5μm ordinarily from the finishing surface roughness of the ceramic material body to be polished. The bonder of this powder is to be mixed for binding mutually with a low binding force the aluminum nitride powder as abrasive grains by the surface tension or sticking force of the binder, and water, alkali solution, acid solution and other salt class water solution, high polymer solution, oil-like liquid, magnetic fluid, resin solution, etc., are employed. The spontaneous action of the polishing layer of a polishing grindstone S1 thus made becomes excellent and a ceramic material 3 is polished with a high efficiency.