This study aimed to investigate the carbonization rate and energy for carbonization of granular waste biomass by superheated steam (SHS) treatment combined with far-infrared heating (FIH) (SHS＋FIH). Cooked and dried rice grains were used as a sample. Carbonization temperatures ranging from 503 to 578K were adjusted by combining SHS temperatures with FIH temperatures. Carbonization rate determined by changes of sample weight during carbonization treatment depended on the carbonization temperature and obeyed the Arrhenius equation. The energy requirement per unit mass of carbonized product, Qc, decreased as carbonization temperature increased. In the combined treatment of SHS＋FIH, the apparatus heated easily and rapidly to the carbonization temperature only when 1/6～1/7 of heat flow (thermal energy rate) to generate SHS was supplied to the FIH heater, and the warm-up time of the apparatus decreased to about half that of the treatment with SHS alone. Results of the increase in productivity of the carbonized product and decrease in carbonization energy as carbonization temperature increased confirmed the energetic advantages of the combined treatment of SHS＋FIH. At carbonization temperatures higher than 623K, it is estimated that the combustion heat of the carbonized product would be several times higher than the carbonization energy.