To provide a method for producing a dried powdery soybean in a relatively short time which contains almost no substance except ingredients of soybean, is resistant to oxidation, and is excellent in shelf life. The method comprises: (Immersing step) wherein water-washed soybeans and tocopherol are immersed in water for a certain time; (Steaming step) wherein the immersed soybeans are steamed; (Crushing step) wherein the steamed soybeans are crushed to a specified size; (Enzyme treating step) wherein a pectinase enzyme and the tocopherol are supplied to the crushed soybeans to prepare a mixture solution, then the mixture solution is agitated for a specified time at an activation temperature of the pectinase enzyme; (Deactivating step) wherein the mixture solution after the enzyme treatment is rapidly heated to deactivate the enzyme, then rapidly cooled; (Separating step) wherein the mixture solution is passed through a screen to micropulverize the solid material to a single cell level, then separated to obtain a slurry; (Drying step) wherein the slurry is dried by spray drying to obtain the dried powdery soybean.