The thin film of tin oxide was formed in the solution containing 0.005–0.3 mol/l SnF₂. The procedure of film formation was very simple; the solution, in which a substrate is immersed, is maintained above 40°C for tens of hours. In this method, the hydrolysis product of SnF₂ deposited as the film on a substrate. As-deposition film included 6–16 mol% fluorine. The chemical component was deduced as SnO_2−05xF_x, where 0.17<×<0.5. The film was modified to pure SnO₂ by heating above 300°C. The electrical conductivity was improved to 1.4×10⁻² Ω cm by heating at 500°C. The model of liquid phase deposition was proposed to extend another oxide film.