Surfactant composition

A surfactant composition, comprising:

• 0.2% by mass to 2.6% by mass of an anionic surfactant (A);
• 0.2% by mass to 3.7% by mass of a cationic surfactant (B);
• a liquid oil (C) and
• water,
• wherein:
• the water constitutes a continuous phase;
• the following molar ratio RA is 0.40 or more and 0.60 or less:
• RA:
• a molar ratio {(A)/[(A)+(B)]} of an amount of the anionic surfactant (A) to a total amount of the anionic surfactant (A) and the cationic surfactant (B);
• the following molar ratio Rb is 0.7 or more:
• Rb:
• a molar ratio {[(a1)+(b1)]/[(A)+(B)]} of a total amount of a branched anionic surfactant (a1) and a branched cationic surfactant (b1) to the total amount of the anionic surfactant (A) and the cationic surfactant (B);
• the branched anionic surfactant (a1) is represented by the following formula (1):
• wherein:
• R1 and R2 each independently represent a hydrocarbon group which may comprise a substituent or a connecting group;
• the total carbon number of R1 and R2 is 5 or more and 29 or less;
• Y represents a single bond or a phenylene group;
• Z represents a group selected from a —SO3 group and a —OSO3 group;
• and
• M represents a cation;
• and
• the cationic surfactant (B) is at least one quaternary ammonium salt cationic surfactant selected from those represented by any of the following general formulae (2) and (3):
• wherein:
• R3 and R4 each independently represent a hydrocarbon group having 6 or more and 26 or less carbon atoms;
• R5 and R6 each independently represent an alkyl group having 1 or more and 3 or less carbon atoms;
• and
• X− represents an anion,
• and
• wherein:
• R7, R8, and R9 each independently represent an acyl group having 8 or more and 22 or less carbon atoms or a hydrogen atom, provided that R7, R8, and R9 are not a hydrogen atom at the same time;
• R10 represents an alkyl group having 1 or more and 3 or less carbon atoms;
• and
• X− represents an anion.