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′), by reacting a carboxylic acid represented by the following formula (a2) to an epoxy silane represented by the following formula (a1) 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. R1 denotes a substitutent with 1 to 20 carbons having a polymerizable group. R2 to R4 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.