A method for producing a protein composition that suppresses changes such as degradation / denaturation of proteins occurring when protein irradiation is performed on a protein denatured by completely removing water or a protein with high hydrophilicity It is aimed to provide.The method for producing a protein composition of the present invention comprises the steps of: forming a hydrogen bond, which is one or more selected from the group consisting of proteins (A), radical scavengers (RS), amino acids, peptides, and proteins other than the protein (A) (HC), wherein the method for producing the protein composition comprises a sterilization step of sterilizing the pre-sterilization protein composition by radiation, wherein the pre-sterilization protein composition Comprises a protein (A), the radical scavenger (RS), and a compound capable of forming the hydrogen bond (HC), wherein the protein (A) is a sulfide group, an amide group, a hydroxyl group, A compound (HC) having one or more kinds of functional groups selected from the group consisting of an amino group and a carboxyl group and capable of forming the hydrogen bond is At least one functional group selected from the group consisting of an amide group, an amide group, a hydroxyl group, an amino group and a carboxyl group, and a functional group in the protein (A), a compound capable of forming the hydrogen bond (HC) can be bound by hydrogen bonding, and the moisture content in the protein composition before sterilization is 0 to 30% by weight based on the weight of the protein composition before sterilization , The weight ratio [radical scavenger (RS) / protein (A)] of the radical scavenger (RS) and the protein (A) in the pre-sterilization protein composition is 0.01 to 1.0, A molar ratio of the total molar number of the functional groups of the compound (HC) capable of forming the hydrogen bond in the protein composition before sterilization to the total number of moles of the functional group in the protein (
