An organodisiloxane represented by the general formula: R.sup.1 R.sup.2 R.sup.3 SiOSiR.sup.4 R.sup.5 R.sup.6 is reacted with thionyl chloride in the presence of an ammonium salt represented by the general formula: R.sup.7 R.sup.8 R.sup.9 R.sup.10 NX wherein R.sup.1 to R.sup.5 and R.sup.10 may be the same or different and each represents a monovalent hydrocarbon group or a hydrogen atom; R.sup.7 to R.sup.9 may be the same or different and each represents a monovalent hydrocarbon group; and X represents a monovalent anion. Thus, organomonochlorosilanes represented by R.sup.1 R.sup.2 R.sup.3 SiCl and R.sup.4 R.sup.5 R.sup.6 SiCl can be obtained.