PURPOSE: To remove foundation powder without injuring the surface of a sintered body in a method by which a semiconductor porcelain sintered body is barrel-polished in slurry by using slurry adjusted into specified viscosity by means of alumina powder and more than one kinds of ceramic powder.

CONSTITUTION: An intergranular insulated type semiconductor porcelain element having strontium titanate and the like as main component which is utilized as a composite functional element such as a semiconductor porcelain condenser or a nonlinear voltage element having electrostatic capacity, uses foundation power of the same main component as that of a sintered body for preventing mutual seizure between the sintered bodies in the burning process. For removing the foundation powder after the burning process, the semiconductor porcelain sintered body is barrel-polished in slurry. The slurry adjusted into the viscosity of 100-600cps by means of alumina powder of regulated grain size and move than one kind of ceramic powder selected from zirconia powder or the same powder as the main component of the semiconductor porcelain is used. Hereby, stable removal of the foundation powder is realized.