A method for producing an organopolysiloxane emulsion composition, the method comprising the steps of: preparing an emulsion composition by emulsifying a mixture comprising 100 parts by weight of organopolysiloxane of general formula below, which has an octamethylcyclotetrasiloxane content of not more than 1,000 ppm HO(R 1 2 SiO) n H wherein each R 1 is independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms, and n is a number such that the organopolysiloxane has a viscosity at 25°C of at least 200 mm 2 /s and less than 2,000 mm 2 /s as measured with an Ostwald viscometer, from 1 to 8 parts by weight of surfactant of general formula below, having an alkylnaphthalene skeleton R 2 a -C 10 H (7-a) -SO 3 M wherein R 2 is a linear or branched alkyl group of 1 to 30 carbon atoms; M is a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an ammonium ion or a tertiary ammonium ion; and a is an integer from 1 to 3, and (C-1) from 1 to 10,000 parts by weight of water; and after optionally adding to the resulting emulsion composition (C-2) from 0 to 10,000 parts by weight of water, carrying out emulsion polymerization at a temperature below 40°C in the presence of an acid catalyst, provided that addition of the acid catalyst may be omitted when the surfactant has a catalytic action, wherein the organopolysiloxane that forms has a viscosity at 25°C of at least 300,000 mPa·s as measured with a rotational viscometer, the amount of octamethylcyclotetrasiloxane included in the organopolysiloxane is not more than 3,000 ppm, and the average size of the resulting emulsion particles is not more than 500 nm as measured by laser diffraction/scattering method. preparing an emulsion composition by emulsifying a mixture comprising 100 parts by weight of organopolysiloxane of general formula below, which has an octamethylcyclotetrasiloxane content of not more than 1,000 ppm HO(R 1 2 SiO) n H wherein each R 1 is independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms, and n is a number such that the organopolysiloxane has a viscosity at 25°C of at least 200 mm 2 /s and less than 2,000 mm 2 /s as measured with an Ostwald viscometer, from 1 to 8 parts by weight of surfactant of general formula below, having an alkylnaphthalene skeleton R 2 a -C 10 H (7-a) -SO 3 M wherein R 2 is a linear or branched alkyl group of 1 to 30 carbon atoms; M is a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an ammonium ion or a tertiary ammonium ion; and a is an integer from 1 to 3, and (C-1) from 1 to 10,000 parts by weight of water; and 100 parts by weight of organopolysiloxane of general formula below, which has an octamethylcyclotetrasiloxane content of not more than 1,000 ppm HO(R 1 2 SiO) n H wherein each R 1 is independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms, and n is a number such that the organopolysiloxane has a viscosity at 25°C of at least 200 mm 2 /s and less than 2,000 mm 2 /s as measured with an Ostwald viscometer, from 1 to 8 parts by weight of surfactant of general formula below, having an alkylnaphthalene skeleton R 2 a -C 10 H (7-a) -SO 3 M wherein R 2 is a linear or branched alkyl group of 1 to 30 carbon atoms; M is a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an ammonium ion or a tertiary ammonium ion; and a is an integer from 1 to 3, and (C-1) from 1 to 10,000 parts by weight of water; and after optionally adding to the resulting emulsion composition (C-2) from 0 to 10,000 parts by weight of water, carrying out emulsion polymerization at a temperature below 40°C in the presence of an acid catalyst, provided that addition of the acid catalyst may be omitted when the surfactant has a catalytic action, (C-2) from 0 to 10,000 parts by weight of water, carrying out emulsion polymerization at a temperature below 40°C in the presence of an acid catalyst, provided that addition of the acid catalyst may be omitted when the surfactant has a catalytic action,