To enhance a working efficiency by preventing an after-tack of a natural paint applied on a surface of wood without requiring much time.

The method comprises the first painting step where the natural paint B containing a drying oil or semidrying oil is applied on a surface A1 of wood A and the second painting step where an aqueous solution C containing at least a protein is further applied after a specified time from the above first painting step as a finishing coat on a painted surface B1 with the above natural paint B.