To solve large problems such as nutrient destruction and long drying treatment time, because conventional methods for producing soy milk are based on methods for producing Tofu, wherein soybeans are dried by an oven drying method or a heat drying method, and further large problems such as environmental pollutions, treatment cost increase and the like from the aspect of the treatments of bean curd lees as industrial wastes.

By this method for freeze-drying the soybeans of raw material, the soybeans can be dried in a short time without using heat. Therefore, the maintenance of nutritive ingredients, the improvement in operation efficiency due to short time treatments, the removal of wastes by their pulverization, and the like can be achieved.