PURPOSE: To obtain a pigment dispersant excellent in dispersing capacity by using a lactone-modified amine compd. obtained by reacting a polyalkylenepolyamine compd. with a carboxyl group-terminated polyester obtained by copolymerizing a hydroxycarboxylic acid and a specific lactone compd.

CONSTITUTION: A pigment dispersant is obtained by using a lactone-modified amine compd. obtained by reacting a polyalkylenepolyamine compd. with carboxyl group terminated polyester obtained by copolymerizing a hydroxycarboxylic acid with a lactone compd. represented by the general formula. This pigment dispersant is excellent in dispersing capacity and imparts excellent appearance to coating film because it is high in compatibility with respect to coating vehicle and has the close adhesiveness to the surface of metal.