This invention provides a process for producing of a silicone compound which includes a synthesis reaction of a silicone compound represented by the following formulas (a) and/or (a'), ##STR00001## by reacting a carboxylic acid represented by the following formula (a2) ##STR00002## to an epoxy silane represented by the following formula (a1) ##STR00003## in presence of a metal salt of the carboxylic acid represented by the general formula (a2), characterized in that the reaction is carried out in presence of 0.05 wt % or more water in said reaction system. Here, A denotes siloxanyl group. R.sup.1 denotes a substitutent with 1 to 20 carbons having a polymerizable group. R.sup.2 to R.sup.4 respectively and independently denote hydrogen, a substituted or unsubstituted substitutent with 1 to 20 carbons, or --X-A. X denotes a substituted or unsubstituted divalent substitutent with 1 to 20 carbons.