[Problems] To provide a process for efficiently producing trichlorosilane on an industrial scale by efficiently reusing the waste gas of after trichlorosilane is separated by condensation from the gas that is formed by the reaction of metallic silicon with hydrogen chloride.[Means for Solution] A process for producing trichlorosilane, including, independently from each other, a first production process for forming trichlorosilane by reacting metallic silicon with hydrogen chloride and a second production process for forming trichlorosilane by reacting metallic silicon with tetrachlorosilane and hydrogen; whereintrichlorosilane and other chlorosilane compounds are separated by condensation from trichlorosilane-containing gases formed by reaction in the first production process, and the waste gas from which trichlorosilane and other chlorosilane compounds have been separated by condensation is fed as a hydrogen source to the second production process.