To produce an aqueous resin composition of chlorinated polyolefins without using an emulsifying agent and to provide the aqueous resin composition having good dispersibility and storage stability by making particles of the resin composition finer than particles of a conventional aqueous resin composition while keeping good coated film properties.

The aqueous resin composition is obtained by finely dispersing an acid-modified chlorinated polyolefin, obtained by carrying out graft copolymerization of at least one kind of polymer selected from polypropylene and a propylene-α-olefin copolymer and a polypropylene and propylene-α-olefin copolymer polymerized by a metallocene catalyst with at least one kind of monomer selected from α, β-unsaturated carboxylic acid and its acid anhydride and then chlorinating the graft copolymer, into water by using an ether-based solvent, an alcohol-based solvent and a basic substance without using an emulsifying agent.