PURPOSE: To obtain the title composition containing a zirconiumtetraalkoxide, tetraalkoxysilane, diketone, organic solvent and water at a specific ratio and capable of providing a coating film having excellent initial adhesion, resistance to boiling water and resistance to acids.

CONSTITUTION: The objective coating composition containing (A) a zirconiumtetraalkoxide expressed by formula I (R1 is 1-5C aliphatic hydrocarbon), (B) a tetraalkoxysilane expressed by formula II (R2 is 1-5C aliphatic hydrocarbon), (C) a β-diketone such as acetylacetone or benzoylacetone, (D) an organic solvent such as isopropyl alcohol and (E) water, having molar ratios of the above-mentioned components expressed by the following ranges; component B/component A=0.25-2.5, component C/component A=0.5-6, component D/ components (A+B)=0.05-500 and component E/components (A+B)=0.02-2 and capable of storing for a long period.