In this study, repeated-batch fermentation (14,15) which reuses S. cerevisiae cells was employed, and three varieties of sweet sorghum,i.e., FS902, FS501, and KCS105, as a carbon source, and Saccharomyces cerevisiae strains NBRC 0216 (Taiken No. 396) (16) and Hitachi as a yeast were used for ethanol production, respectively.