A liquid material is applied by spin coating it onto a first main surface of a flat plate to form a coating of the liquid material thereon. The flat plate includes a second main surface which is opposite to the first main surface and a hole which passes through the flat plate. The application of the liquid material is carried out using an inner guide member, which is placed in the hole, and the spin coating is carried out while the flat plate is placed on a stage such that the inner guide member is placed generally adjacent to an inner peripheral side surface of the flat plate and an upper surface of the inner guide member and the first main surface are located at generally the same level. Thereby, a coating is obtained which extends on the upper surface of the inner guide member and the first main surface of the flat plate.