The present invention provides an excellent radiation curable aqueous coating composition, which is highly safe and can make the adhesion to a metal surface and the corrosion resistance compatible which have been considered to conflict with each other, particularly adhesion after severe working and solvent resistance, and particularly durability to alcohols having high polarity. The composition of the present invention contains (1) a phosphoric acid ester compound having an ethylenically unsaturated double bond, (2) an aqueous polyurethane resin having both an ethylenically unsaturated double bond and a group capable of forming a salt, and (3) colloidal silica.