To develop a coating composition for plastics, excellent in compatibility, coating stability and physical properties of its coating film.

The coating composition contains a mixture of an acrylic resin and a chlorinated polyolefin resin, and/or their reaction product. The acrylic resin is obtained as follows: a macromonomer is manufactured by copolymerizing at lest one kind of copolymerizable monomer (a) selected from methacrylic acid and a methacrylic acid ester, with a copolymerizable unsaturated monomer (b) in the presence of a metal complex of a catalytic chain transfer agent or an addition cleavage-type chain transfer agent, and a radical polymerization initiator if necessary; and subsequently, the obtained macromonomer is copolymerized with a copolymerizable unsaturated monomer (c) to obtain the acrylic resin.