PURPOSE: A producing method of a fermented product of mixed grains using lactic acid bacteria is provided to reduce the fermentation time for obtaining the fermented product. CONSTITUTION: A producing method of a fermented product of mixed grains using lactic acid bacteria comprises the following steps: mixing 1part of mixed grain powder by weight, with 0.05~0.2parts of mixed lactic acid bacteria by weight； pouring 3~5parts of liquid milk by weight at 25~35deg C into the mixed grain powder； and fermenting the mixture at 35~38deg C using a culturing device. The mixed grain powder is obtained by wet-milling more than two kinds of grains, and hot-air drying the milled grains.본 발명은 혼합곡물분말과 유산균을 혼합하는 단계； 및상기 혼합물에 액상우유를 투입하여 유산균 발효하는 단계를 포함하는 혼합곡물 발효물의 제조방법을 제공한다.
