Provided is a superior method of producing reduced glutathione by electroreduction of oxidized glutathione. In a method of producing reduced glutathione by electroreduction of oxidized glutathione using a cathode cell and an anode cell separated from each other by a separating membrane, oxidized glutathione is produced using an aqueous oxidized glutathione solution with pH 2.0-3.0 comprising a conducting agent other than acid as a solution in the cathode cell.