A surfactant composition comprising anionic surfactant, cationic surfactant, and dimethylpolysiloxane, wherein the following molar ratio R A is 0.10 or more and 0.90 or less; and the following molar ratio R b is 0.4 or more: R A: a molar ratio { /[ +]} of the amount of anionic surfactant to the total amount of anionic surfactant and cationic surfactant R b: a molar ratio {[ +]/[ +]} of the total amount of branched-type anionic surfactant and branched-type cationic surfactant to the total amount of anionic surfactant and cationic surfactant; wherein the surfactant composition comprises branched-type anionic surfactant and branched-type cationic surfactant; wherein the branched-type anionic surfactant is at least one selected from an internal olefin sulfonate, a secondary alkanesulfonate, and a dialkylsulfosuccinate, and wherein the branched-type anionic surfactant is represented by the following general formula, and the branched-type cationic surfactant is at least one represented by any of the following general formulae and: wherein, R 1 and R 2 each independently represent a hydrocarbon group which may contain a substituent or a connecting group; the total carbon number of R 1 and R 2 is 5 or more and 29 or less; Y represents a single bond; Z - represents a group selected from a -SO 3 - group and a -OSO 3 - group; and M + represents a cation; wherein, R 3 and R 4 each independently represent a hydrocarbon group having 6 or more and 26 or less carbon atoms; R 5 and R 6 each independently represent an alkyl group having 1 or more and 3 or less carbon atoms; and X - represents an anion; and wherein, R 7 and R 8 each independently represent an acyl group having 10 or more and 20 or less carbon atoms and R 9 represents a hydrogen atom or R 7, R 8, and R 9 each independently represent an acyl group having 10 or more and 20 or less carbon atoms; R 10 represents an alkyl group having 1 or more and 3 or less carbon atoms; and X - represents an anion. the following molar ratio R A is 0.10 or more and 0.90 or less; and the following molar ratio R b is 0.4 or more: R A: a molar ratio { /[ +]} of the amount of anionic surfactant to the total amount of anionic surfactant and cationic surfactant R b: a molar ratio {[ +]/[ +]} of the total amount of branched-type anionic surfactant and branched-type cationic surfactant to the total amount of anionic surfactant and cationic surfactant; wherein the surfactant composition comprises branched-type anionic surfactant and branched-type cationic surfactant; wherein the branched-type anionic surfactant is at least one selected from an internal olefin sulfonate, a secondary alkanesulfonate, and a dialkylsulfosuccinate, and wherein the branched-type anionic surfactant is represented by the following general formula, and the branched-type cationic surfactant is at least one represented by any of the following general formulae and: wherein, R 1 and R 2 each independently represent a hydrocarbon group which may contain a substituent or a connecting group; the total carbon number of R 1 and R 2 is 5 or more and 29 or less; Y represents a single bond; Z - represents a group selected from a -SO 3 - group and a -OSO 3 - group; and M + represents a cation; wherein, R 3 and R 4 each independently represent a hydrocarbon group having 6 or more and 26 or less carbon atoms; R 5 and R 6 each independently represent an alkyl group having 1 or more and 3 or less carbon atoms; and X - represents an anion; and wherein, R 7 and R 8 each independently represent an acyl group having 10 or more and 20 or less carbon atoms and R 9 represents a hydrogen atom or R 7, R 8, and R 9 each independently represent an acyl group having 10 or more and 20 or less carbon atoms; R 10 represents an alkyl group having 1 or more and 3 or less carbon atoms; and X - represents an anion. R A: a molar ratio { /[ +]} of the amount of anionic surfactant to the total amount of anionic surfactant and cationic surfactant R b: a molar ratio {[ +]/[ +]} of the total amount of branched-type anionic surfactant and branched-type cationic surfactant to the total amount of anionic surfactant and cationic surfactant; wherein the surfactant composition comprises branched-type anionic surfactant and branched-type cationic surfactant; wherein the branched-type anionic surfactant is at least one selected from an internal olefin sulfonate, a secondary alkanesulfonate, and a dialkylsulfosuccinate, and wherein the branched-type anionic surfactant is represented by the following general formula, and the branched-type cationic surfactant is at least one represented by any of the following general formulae and: wherein, R 1 and R 2 each independently represent a hydrocarbon group which may contain a substituent or a connecting group; the total carbon number of R 1 and R 2 is 5 or more and 29 or less; Y represents a single bond; Z - represents a group selected from a -SO 3 - group and a -OSO 3 - group; and M + represents a cation; wherein, R 3 and R 4 each independently represent a hydrocarbon group having 6 or more and 26 or less carbon atoms; R 5 and R 6 each independently represent an alkyl group having 1 or more and 3 or less carbon atoms; and X - represents an anion; and wherein, R 7 and R 8 each independently represent an acyl group having 10 or more and 20 or less carbon atoms and R 9 represents a hydrogen atom or R 7, R 8, and R 9 each independently represent an acyl group having 10 or more and 20 or less carbon atoms; R 10 represents an alkyl group having 1 or more and 3 or less carbon atoms; and X - represents an anion.