PURPOSE: To provide an anionic electrodeposition paint containing an aqueous vehicle made from an anionic resin and (a) reaction product of orthophosphoric acid monoester with an epoxy resin, and forming a coating film excellent in smoothness, transparency and acid resistance.

CONSTITUTION: The titled paint is prepared by adding 1W30wt% reaction product of orthophosphoric acid monoester of the formula (where R is oleyl or 1W 20C alkyl) (e.g. monobutyl orthophosphate) and an epoxy resin, to 99W70wt% anionic resin (e.g. maleinized polybutadiene, epoxy resin ester, or water soluble phenolic resin, pref. containing a crosslinking resin). The paint forms a film excellent in smoothness, transparency and resistance to acid and corrosion and is esp. suitable for clear finishing of aluminum (alloy), etc. to retain inherent aesthetic properties of substrate.