To provide a grain-drying method and a device for effectively utilizing rice hulls, straw rubbish, their fragments, organic impurities, and harvest waste such as the organic dust/dirt being generated in the harvest-manufacturing process of other cereals as a heat source.

The harvest waste is dried by distillation and is thermally decomposed into a carbide and a gas constituent, and then the gas constituent is mixed with the carbide for combustion. The combustion surplus of the carbide is allowed to burn while it is collected continuously.