PURPOSE: To provide the titled composition capable of imparting coated metallic objects with outstanding corrosion and scratch resistances and coating film adhesiveness, comprising a chromic chromate compound, granular silicon oxide compound, water-swellable laminar silicate compound and water-dispersible organic resin, etc.

CONSTITUTION: The objective composition comprising (A) a chromic chromate compound containing hexavalent chromium and trivalent chromium [pref., the amount of hexavalent chromium accounting for 20W80wt.% on a CrO3 basis, of the total amount of chromium], (B) a granular silicon oxide compound (pref., with a size 0.01W5μ), (C) a water-swellable laminar silicate compound (e.g., montmorillonite), and (D) a water-dispersible or water-soluble organic resin (e.g., acrylic resin). The concentration of the component C is pref. 0.1W10wt.% or a solid content basis in the composition liquid.