The author isolated bacteria from the putrefied moromi-mash of saké and its service-water from the well in Saitama-prefecture separately. It was found that these two bacteria could be classified into the same species after the studies of morphological and physiological characters. It was very similar to Micrococcus sidt.vrems-magnus ODA. and named Micrococcus sake KATO by reasan of some different properties for the sugar fermentation and the most moderate temperature of cultivation.