A raw material recovery method for recovering a raw material of an organic metallic compound, which has the property of being stable toward a specific refrigerant without being decomposed thereby, from exhaust gas discharged from a treatment container in which a metallic thin film is formed on the surface of an object to be treated by using source gas obtained by vaporizing the raw material is characterized by being provided with a solidification step for solidifying the unreacted source gas by cooling the exhaust gas by bringing the exhaust gas into contact with the refrigerant and reprecipitating the raw material, and a recovery step for separating and recovering the raw material reprecipitated in the solidification step from the refrigerant. To provide a method for controlling an exhaust gas flow rate so that flow of gas in a processing chamber becomes uniform.