Abstract: Disclosed is an aqueous mid-coat paint composition comprising a water-soluble or water-dispersible polyester resin (A) having from 2 to 10 mass % of polyethylene glycol groups or polyethylene glycol ether groups of number average molecular weight from 300 to 600; carboxylic acid secondary or tertiary amine salt groups obtained by neutralizing carboxylic acid groups; a total number of from 0.8 to 1.2 of said polyethylene glycol groups or polyethylene glycol ether groups and said carboxylic acid secondary or tertiary amine salt groups per number average molecular weight of the resin; and (B) a melamine resin as curing agent, wherein the ratio by mass of the resin solid fractions of the (A) component and the (B) component is from 75/25 to 90/10.