Disclosed herein is a solid polymer electrolyte wherein protons of cation exchange groups contained in a perfluorinated electrolyte are partially replaced by metal ions. The metal ion is at least one metal ion selected from vanadium (V), manganese (Mn), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), ruthenium (Ru), nickel (Ni), palladium (Pd), platinum (Pt), silver (Ag), cerium (Ce), neodymium (Nd), praseodymium (Pr), samarium (Sm), cobalt (Co), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), and erbium (Er) ions. Further disclosed is a solid polymer fuel cell using the solid polymer electrolyte.