Abstract: The present invention aims at providing an apparatus for and a method of forming low-temperature oxide films, which are capable of forming an oxide film at a low temperature and preventing the diffusion of impurities from the outside. The apparatus for forming an oxide film at a low temperature is characterized in that it has an oxidation furnace provided with a gas supply port and a gas discharge port, a heater for heating the oxidation furnace to a predetermined temperature, and a gas supply system disposed upstream of the oxidation furnace and provided with a means for adding an arbitrary quantity of water or a means for generating an arbitrary quantity of water.