PURPOSE: To obtain a fermented product useful as a feed or fertilizer, rich in protein, fats and digestive enzymes by effectively using waste, by growing KOJI mold in a mixture of waste liquor of low-class distilled spirits and a grain raw material and drying a fermented substance by using heat of fermentation.

CONSTITUTION: Waste liquor or low-class distilled spirits is blended with a grain raw material such as wheat bran, rice bran, corn starch or rice flour and/or fibrous raw material such as rice hulls or sawdust to give a mixture having ≤65wt.% water content. Then the mixture is inoculated with a KOJI mold belonging to the genus Aspergillus to grow the KOJI mold, the KOJI mold is produced and the mixture is dried by sending warm air at 30W50°C by using heat of fermentation thereof and optionally warm air heated to ≥30°C to give a fermented product.