A method for producing metallic silver by electro-deposition, including electrolyzing an electrolyte solution containing Ce(NO3)3 in an anode zone and an electrolyte solution containing AgNO3 in a cathode zone by using an electrolytic cell with a specific diaphragm, wherein the electrolyte solution in the anode zone is not allowed to enter the cathode zone. After the electrolyzing is complete, the metallic silver with a high purity is obtained at the cathode, and a Ce4+-containing solution is obtained in the anode zone.