It is intended to provide a soybean protein material which is highly dispersible in hot water and highly miscible with water so as to give a solution showing regulated coarseness. More specifically, it is intended to provide a soybean protein material which is appropriately usable in preparing protein drinks. According to a method comprising the following steps, it becomes possible to produce a soybean protein material which is dispersible in hot water and miscible with water: the step wherein soybean protein is hydrolyzed with a protease in an aqueous system until the 0.22 MTCA solubility attains 15 to 30% the step wherein an emulsifier having an HLB value of 6 or more but not more than 13 is added to the soybean protein the step of drying the soybean protein after the hydrolysis and the step of heating the soybean protein in an aqueous system at 105 to 180°C for 15 to 180 seconds before the drying.
