A surface-treating composition comprising a fluorine-containing polymer wherein the surface-treating composition comprises: at least one first compound represented by any of the following general formulae and: wherein: Rf is an alkyl group having 1 to 16 carbon atoms which may be substituted by one or more fluorine atoms; R 1 is a group represented by the following formula: - (OC 4 F 8) v -(OC 3 F 6) a -(OC 2 F 4) b -(OCF 2) c - wherein: a, b, c and v are each independently an integer of 0 or more and 200 or less, wherein the sum of a, b, c and v is at least one, and the occurrence order of the respective repeating units in parentheses is not limited in the formula; R 2 is a group represented by the following formula: - d - e -(CH 2) f - wherein: Q is an oxygen atom or a divalent polar group; Z is a fluorine atom or a fluoroalkyl group having 1-3 carbon atoms; and d, e and f are each independently an integer of 0 or more and 50 or less, wherein the sum of d, e and f is at least one, and the occurrence order of the respective repeating units in parentheses is not limited in the formula; T is a hydroxyl group or a hydrolyzable group; R 3 is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms; n is an integer from 1 to 3; R 4 is a group represented by the following formula: wherein: Y is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and g is an integer of 0 or more and 50 or less; X is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom; and m is an integer of 1 or more and 10 or less; and at least one second compound represented by the following general formula: Rf-R 1' -Rf' wherein: Rf is an alkyl group having 1 to 16 carbon atoms which may be substituted by one or more fluorine atoms; Rf' is an alkyl group having 1 to 16 carbon atoms which may be substituted by one or more fluorine atoms, a fluorine atom or a hydrogen atom; R 1' is a group represented by the following formula: -(OC 4 F 8) w -(OC 3 F 6) r -(OC 2 F 4) s -(OCF 2) t - wherein: r, s, t and w are each independently an integer of 0 or more and 300 or less, wherein the sum of r, s, t and w is at least one, and the occurrence order of the respective repeating units in parentheses is not limited in the formula; the proportion of the first compound is 15 to 70% by mass with respect to the total mass of the first compound and the second compound; and the number average molecular weight of the at least one second compound is by 2,000 or more higher than the number average molecular weight of the at least one first compound, wherein the number average molecular weight is determined by 19 F-NMR. Rf is an alkyl group having 1 to 16 carbon atoms which may be substituted by one or more fluorine atoms; R 1 is a group represented by the following formula: a, b, c and v are each independently an integer of 0 or more and 200 or less, wherein the sum of a, b, c and v is at least one, and the occurrence order of the respective repeating units in parentheses is not limited in the formula; R 2 is a group represented by the following formula: - d - e -(CH 2) f - Q is an oxygen atom or a divalent polar group; Z is a fluorine atom or a fluoroalkyl group having 1-3 carbon atoms; and d, e and f are each independently an integer of 0 or more and 50 or less, wherein the sum of d, e and f is at least one, and the occurrence order of the respective repeating units in parentheses is not limited in the formula; T is a hydroxyl group or a hydrolyzable group; R 3 is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms; n is an integer from 1 to 3; R 4 is a group represented by the following formula: Y is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and g is an integer of 0 or more and 50 or less; X is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom; and m is an integer of 1 or more and 10 or less; and at least one second compound represented by the following general formula: Rf is an alkyl group having 1 to 16 carbon atoms which may be substituted by one or more fluorine atoms; Rf' is an alkyl group having 1 to 16 carbon atoms which may be substituted by one or more fluorine atoms, a fluorine atom or a hydrogen atom; R 1' is a group represented by the following formula: r, s, t and w are each independently an integer of 0 or more and 300 or less, wherein the sum of r, s, t and w is at least one, and the occurrence order of the respective repeating units in parentheses is not limited in the formula; the proportion of the first compound is 15 to 70% by mass with respect to the total mass of the first compound and the second compound; and the number average molecular weight of the at least one second compound is by 2,000 or more higher than the number average molecular weight of the at least one first compound, wherein the number average molecular weight is determined by 19 F-NMR.