The present invention relates to a soybean, which can be easily processed into a food containing free amino acids and has a high total free amino acid content in the seeds thereof, and a method of producing such soybean. By providing a soybean characterized in that it genetically lacks all subunits of .beta.-conglycinin and glycinin, or has only A.sub.3B.sub.4, which is the subunit of glynicin among the subunits of .beta.-conglycinin and glycinin, a soybean having a total free amino content in the seeds thereof which is greater than those of general soybean varieties, is provided.