To provide a resin composition capable of forming a thin film layer so as to cause tenting over concave portions by conventional coating processes without depending on dry films, and also a coating method so as to cause tenting of the resin composition. A resin composition, which, by spin coating, causes tenting over concave portions formed on a substrate, the resin composition including a resin component (a) and a solvent (b) and has a viscosity of at least 200 cP, and tenting can be achieved by using the resin composition, allowing the resin composition to fall drop wise onto a substrate on which concave portions are formed, and spin coating the substrate at a rotating speed of 300 to 4000 rpm.