The object is to fractionate 7S-globulin as well the remaining acid-precipitatable proteins from a soybean with efficiency and at high purities, and provide a highly pure fractionated soybean protein material. Specifically disclosed is a method for producing a fractionated soybean protein material, which comprises the steps of: 1) extracting a protein from a soybean having a 7S-globulin content of 20 wt % or more and a 11S-globulin content of 10 wt % or less relative to the total amount of proteins, thereby producing a soybean protein solution 2) adjusting the pH value of the soybean protein solution to 4 to 5.5, and heating the resulting solution at 40 to 65° C. and 3) adjusting the pH value of the heated soybean protein solution to a value ranging from 5.3 to 5.7 and higher than the pH value at the time of the heating the solution, and fractionating the resulting solution into a water-soluble fraction and a water-insoluble fraction.
