A roll coating apparatus for applying a coating liquid having a high viscosity at a normal temperature, to a surface of a substrate, including a device for feeding the substrate, a coating roll rotatably provided in contact with the fed substrate, and a doctor for regulating the coating liquid adhering to the coating roll to a prescribed amount. Respective axial lines of the coating roll and the doctor are inclined with a prescribed angle with respect to the horizontal plane and a coating liquid supply device is provided at the highest position thereof. The coating liquid supplied at the highest end of the coating roll adheres to the surface of the coating roll. The quantity thereof is controlled by the doctor. The coating liquid flows downward on the surface of the coating roll due to its weight and rotation of the coating roll. Accordingly, the coating liquid on the surface of the coating roll is constantly renewed and no irregularities occur to the density of the liquid. The coating liquid is transferred from the coating roll, to form a film having a prescribed uniform thickness on the substrate. This roll coating apparatus may further include a device for heating parts of the apparatus or the substrate to lower the viscosity of the coating liquid. Thus, it becomes possible to form a film of a more uniform and regulated thickness easily.