PURPOSE: To obtain the title composition which is excellent in both spreadability and driability, can be dried in a shorter time than that of conventional one and is markedly improved in workability.

CONSTITUTION: A polyurethane coating composition comprising an isocyanurate structure-containing polyisocyanate obtained by reacting hexamethylene diisocyanate or a mixture thereof with isophorone diisocyanate with polytetramethylene glycol in the presence of an isocyanuration catalyst, a polyol having at least two hydroxyl groups in the molecule, and nitrocellulose in a specified ratio.