Strains of Bacillus sp. SHO-1, Bacillus cereus, Bacillus coagulans, Bacillus subtilis, and Bacillus thuringiensis were anaerobically and aerobically cultured. The cell yields were higher in the aerobic culture, but more lactic acid was produced in the anaerobic culture. The maximum concentration of the lactic acid produced by Bacillus sp. SHO-1, B. cereus, and B. thuringiensis in simple media of Polypepton made from soybeans and glucose were 16.4, 13.3, and 12.0 g/l, respectively. Moreover, the optical purities of the lactic acid produced were 99.0, 98.8, and 96.8%, respectively.