To provide a method for treating a carbonized product to inhibit heat generation by covering the carbonized product with a coating material containing lime and a binder, capable of reducing a cost required for the binder, the preparation and storage of the binder, etc., and performing the treatment for inhibiting the heat generation inexpensively.

On performing the treatment of the carbonized product for inhibiting the heat generation by dry-treating dehydrated sludge C after the dehydration treatment of raw sludge A containing organic materials at a sewage-treating plant, performing a carbonizing treatment of the dried sludge by a carbonizing furnace F to obtain a carbonized product, treating it with a coating material containing the lime and the binder to cover the carbonized product with the coating material to perform the heat generation-inhibiting treatment, an organic polymer agglomerating agent added to the raw sludge A at the sewage-treating plant to agglomerate sludge particles and form flocks is separated and collected from a storage tank D so as to be used as the binder.