To provide a method for fermenting bean curd lees for effective use of bean curd lees and to use the fermented bean curd lees as a feed.

Bean curd lees are formulated with rice bran, fermented by using broadly-defined Bacillus subtilis, the water content of fermented substance is reduced and the qualities of the fermented material are stabilized while keeping the bacteria alive. The self-heating of the fermented substance is utilized in drying and evaporated wafer is absorbed in a hygroscopic material such as a ground material of tree, etc.