By reacting a mixture of a halogenoalkyl group-bearing organosilicon compound and sulfur with an aqueous solution or water dispersion of an ammonium or alkali metal sulfide or a hydrate thereof in the presence of a phase transfer catalyst, a sulfide chain-bearing organosilicon compound having the average compositional formula (2): (R.sup.1O).sub.(3-p)(R.sup.2).sub.pSi--R.sup.3--S.sub.m--R.sup.3--Si(OR.s- up.1).sub.(3-p)(R.sup.2).sub.p (2) wherein m has an average value of 2.ltoreq.m.ltoreq.6 is obtained in high yields and at a low cost with minimized formation of a monosulfide-bearing organosilicon compound.