An electrolyte material, which comprises a polymer having ion exchange groups converted from precursor groups in the following polymer: polymer: a polymer which has repeating units based on a perfluoromonomer having a precursor group of an ion exchange group and a 5-membered ring to which the precursor group is bonded and repeating units represented by the following formula, and which has an intrinsic viscosity of at least 0.3 dL/g: wherein s is 0 or 1, each of R 1 and R 2 which are independent of each other, is a fluorine atom or a C 1-5 perfluoroalkyl group or they are bonded to form a spiro ring (provided that when s is 0), each of R 3 and R 4 which are independent of each other, is a fluorine atom or a C 1-5 perfluoroalkyl group, and R 5 is a fluorine atom, a C 1-5 perfluoroalkyl group or a C 1-5 perfluoroalkoxy group, wherein at least one type of repeating units having ion exchange groups converted from the precursor groups in the repeating units are repeating units represented by the following formula: wherein R f is a linear or branched perfluoroalkyl group which may have an etheric oxygen atom, and X is an oxygen atom, a nitrogen atom or a carbon atom, provided that when X is an oxygen atom, a=0, when X is a nitrogen atom, a=1, and when X is a carbon atom, a=2, R 21 is a C 1-6 perfluoroalkylene group or a C 2-6 perfluoroalkylene group having an etheric oxygen atom between the carbon-carbon bond, R 22 is a fluorine atom, a C 1-6 perfluoroalkyl group, a C 2-6 perfluoroalkyl group having an etheric oxygen atom between the carbon-carbon bond or a -R 21 (SO 2 X(SO 2 R f) a M + group, wherein M + in is H +, and wherein at least one type of the repeating units represented by the formula are repeating units represented by the following formula (u12-1): or wherein at least one type of the repeating units represented by the formula are repeating units represented by the following formula (u12-2): polymer: a polymer which has repeating units based on a perfluoromonomer having a precursor group of an ion exchange group and a 5-membered ring to which the precursor group is bonded and repeating units represented by the following formula, and which has an intrinsic viscosity of at least 0.3 dL/g: wherein s is 0 or 1, each of R 1 and R 2 which are independent of each other, is a fluorine atom or a C 1-5 perfluoroalkyl group or they are bonded to form a spiro ring (provided that when s is 0), each of R 3 and R 4 which are independent of each other, is a fluorine atom or a C 1-5 perfluoroalkyl group, and R 5 is a fluorine atom, a C 1-5 perfluoroalkyl group or a C 1-5 perfluoroalkoxy group, wherein at least one type of repeating units having ion exchange groups converted from the precursor groups in the repeating units are repeating units represented by the following formula: wherein R f is a linear or branched perfluoroalkyl group which may have an etheric oxygen atom, and X is an oxygen atom, a nitrogen atom or a carbon atom, provided that when X is an oxygen atom, a=0, when X is a nitrogen atom, a=1, and when X is a carbon atom, a=2, R 21 is a C 1-6 perfluoroalkylene group or a C 2-6 perfluoroalkylene group having an etheric oxygen atom between the carbon-carbon bond, R 22 is a fluorine atom, a C 1-6 perfluoroalkyl group, a C 2-6 perfluoroalkyl group having an etheric oxygen atom between the carbon-carbon bond or a -R 21 (SO 2 X(SO 2 R f) a M + group, wherein M + in is H +, and wherein at least one type of the repeating units represented by the formula are repeating units represented by the following formula (u12-1): or wherein at least one type of the repeating units represented by the formula are repeating units represented by the following formula (u12-2):