An organic/inorganic composite coating film comprising an inorganic material as a matrix and an organic material combined therewith. The coating film has a regular hollow structure therein, and the coating film surface has a rugged pattern with semispherical protrusions. Also provided is a large-area structural color film obtained by burning the composite coating film. The organic/inorganic composite coating film is obtained by applying an aqueous coating composition comprising a metal alkoxide, an aqueous dispersion of monodisperse polymer particles, and an acid catalyst to a substrate and curing the coating composition. Burning the organic/inorganic composite coating film gives the structural color film.