Abstract: A method and apparatus for coating a plate with a thin liquid film. In the method, a thin liquid film is coated on a surface of a substrate such as a glass plate by using an incomplete liquid tank having an opening of a shape similar to the shape of the substrate surface on one side thereof. The tank communicates with a flow streamlining channel by an aperture in a lower section of the tank. First the substrate and the incomplete tank are brought into tight contact with each other such that the side opening of the tank is closed by the substrate, whereby the tank is completed. Next, a coating liquid such as a metal alkoxide solution is fed into the tank to thereby wet the substrate surface. Preferably the coating liquid is allowed to overflow the tank to remove a surface layer of the liquid. Then the liquid is extracted from the tank through the streamlining channel so as to lower the liquid level in the tank at a predetermined rate while keeping both the tank and the substrate stationary.