PURPOSE: To prepare high-quality soybean milk, by deactivating an enzyme participating in soybean milk odor and an enzyme taking part in nutrition hindrance having different heat temperature and heat time of soybean raw material by heating in different places under proper conditions before it is sent to a hot-water grinder.

CONSTITUTION: In the storage tank 1 for hot water, etc., the cylindrical case 6 having the screw conveyor 5 in it, the hopper 8 at the top of the bottom part, and a great number of the through holes 7 at the periphery of the lower part is set slantingly, the upper projection part wherein the case 6 is protruded to the outside of the storage tank is equipped with the steam jacket 9 having a great number of the steam jet holes 12 on the case 6, the steam inlet 10 is laid at the top of it, and the drain outlet 11 facing the storage tank is set at the bottom part of it. The top of the case 6 is connected to the top of the hopper 28, the hopper 28 is provided with the hot water jet head 29, the water feed chamber 32 having the inlet 31 for hot water, etc. is laid at the bottom of it, the grinding chamber 17 having the ring-shaped steam jacket 27 is laid at the lower part of the water feed chamber, and the grinding chamber is equipped with pulverizers (a) and (b).