To provide an organic waste processor wherein the formation of lumps of processing material is suppressed, and wherein the processing material can be used for a long time period. An organic waste processor 10 comprises a processing tank 12 for processing organic waste, such as kitchen waste. The processing tank 12 contains a material 11 on which microorganisms are supported which aerobically decompose kitchen waste. By sending air from an air pump 20 into the processing tank 12, the water content of the material 11 is decreased, and the formation of lumps due to sticking together of the processing material 11 is thereby suppressed.