PURPOSE: To convert silicon chloride into silicon tetrachloride at a nearly quantitative yield and a relatively low temperature by reacting a gasified silicon chloride having SiH bond with hydrogen chloride in the presence of a palladium catalyst.

CONSTITUTION: The silicon chloride having SiH bond and to be used in the present process is silicon trichloride or silicon dichloride which may contain silicon monochloride. A gaseous mixture of these silicon chlorides and hydrogen chloride is passed through a catalyst layer consisting of palladium chloride, etc., supported on a carrier having high specific surface area and relatively large particle size, e.g. activated carbon and silicon dioxide, at ≥70°C, preferably 100-350°C. The ratio of the hydrogen chloride in the mixture is somewhat excess to the calculated amount of hydrogen chloride necessary for converting the existing silicon trichloride and silicon dichloride in the silicon chloride gas into silicon tetrachloride. The silicon chloride is almost quantitatively reacted with hydrogen chloride by this process to obtain silicon tetrachloride having high purity at a low cost.