PURPOSE: To efficiently regenerate the metallic filter of high performance by a method wherein the metallic filter used in filtration of a fluid of high-polymeric material is subjected to controlled oxidation heating to carbonize the material, then the filter is immersed in an alkaline bath and is subjected to ultrasonic cleaning.

CONSTITUTION: The filter used in filtration of the fluid of high-polymeric material is subjected to preoxidation by preheating the filter at a temperature slightly higher than the melting point of the polymeric material for a predetermined period of time. Next, the filter is subjected to oxidation heating at a predetermined temperature slightly higher than the decomposition point of the material to carbonize the material while preventing inflammation. Then, the filter with the carbide deposited thereon is immersed in the alkaline bath for a predetermined period of time, thereby accelerating the flaking of the carbide. The filter is then subjected to ultrasonic cleaning in hot water or water bath, so that the flaked carbide is dispersed in the water bath in a short time.