To obtain an emulsion, which exhibits a high retention on sound and damaged hair and is able to impart smoothness, softness, antistatic properties and the like to the hair, by emulsifying a specific type of organopolysiloxane containing a carboxyl group and having a predetermined degree of polymerization.

This emulsion is obtained by emulsifying an organopolysiloxane of the formula: R1XR2yR3zSiO(4-x-y-z)/s, which has one or more COOH groups in the molecule and a degree of polymerization of 200 to 20,000. In the formula, R1 represents a 1-20C monovalent hydrocarbon group; R2 represents R1 or OX in which X represents H or a 1-6C monovalent hydrocarbon group; R3 represents a -R4COOH group in which R4 represents a 1-20C divalent by hydrocarbon group; o<x≤2; 0≤y<0.05; 0≤z≤0.15; and 1.8<x+y+z<2.2. The organopolysiloxane of the formula should preferably have units of average formulas of R1aR2bSiO(4-a-b)/2 (A), R3cR2dSiO(4-c-d)/2 (B), and R1SiO3/2 (C) at molar ratios of A:B:C=1:0.001-0.01:0-0.01. In the above formula, 0<a; C≤3; 0≤b; d<3; 1≤a+b; and c+d≤3.