PURPOSE: To obtain the subject emulsion useful as a sizing agent for paper-making use, achieving sizing effect over a wide pH range in paper-making process and having excellent dilution stability by dispersing a rosin substance in water in the presence of a specific dispersing agent.

CONSTITUTION: The objective emulsion is produced by dispersing a rosin substance in water in the presence of a dispersing agent consisting of a compound of formula (R1 is 4-18C alkyl, alkenyl or aralkyl; R2 is H, 4-18C alkyl, alkenyl or aralkyl; R3 is H or methyl; A is 2-4C alkylene or substituted alkylene; n is 1-200; M is univalent cation).