1. Amylase producing bacteria have been isolated from natural sources and was identified out. The above strain is identical to Bacillus subtillis in every details of physiological and morphorogical characteristics by this investigations. 2. Sikworm chrysalis nad chlorella extracts are prove to be further effective for the stimulation of amylase production than any other sources. The former silkworm extract is more stronger in its activity. 3. It is found that effective results had been accepted by a less soybean meal addition per that of wheat bran in the mixture ratio of them, also less addition of corn is needed in the mixture ratio of between corn and whear bran. In the mixing ratio of wheat bran per silkworm or chlorella extracts, the addition of wheat bran is necessary for stimulation of amylase production. 4. Fro the stimulation of amylase production, the effective substances from natural sources and its order of activity in cultral media cultral media is proved as follows, silkworms ext.>chlorella ext.>alcohol>skim-milk and peptone>fermented milk>radish leaf ext.