An electrolyte having a structure where a fluorinated hydrophilic segment A represented by -E2-[Rf-E1]m- and a hydrocarbon hydrophobic segment B are alternately bonded to each other through chemical bond and a production process therefor, and an electrolyte membrane, a production process therefor, a catalyst layer and a fuel cell using the same. Rf is a linear or a branched perfluoro chain having one or more carbon atoms, E1, and E2 are each a proton conductive portion represented by Formula —(CONM)i1(CO)i2(SO2NM)i3(SO2)i4— (0≦i1, 0≦i2≦1, 0≦i3, 0≦i4≦1, 0<i1+i3, i1 to i4 are each an integer, and M is proton, alkali metal, or alkali earth metal), 2≦m (m is an integer), and Rf, E1, and E2 may be each arbitrarily selected in the repeating unit.