Provided is a reactor suitable particularly for the high-temperature gas phase reaction of chlorosilane with hydrogen, which can achieve a high reaction yield by preventing reverse reaction and the like as much as possible while maintaining high heat transfer efficiency. The reactor is provided with a reaction container for causing a gas phase reaction among plural types of source gases supplied at a predetermined inflow rate from an inflow port and discharging resultant gas as a reaction product gas from an outflow port, a heating means for heating the interior of the reaction container, which is attached along the reaction container, and a heat transfer member for increasing the gas flow rate by being disposed in the reaction container to narrow the area of a gas flow path.
