DESCRIZIONE
Provided are an antifouling coating composition which can inhibit thickening compared with conventional antifouling coating compositions, has long-term storage stability, and can exhibit excellent antifouling properties and water resistance (long-term mechanical properties) when a coating film is formed, and related techniques. The antifouling paint composition is obtained by mixing an acryloxysilane copolymer (A) and a rosin compound (B), wherein the acryloxysilane copolymer (A) has a component unit derived from (methyl) acryloxy triisopropylsilane (A1) and a component unit derived from a polymerizable monomer (A2) with a polymerizable double bond, and the rosin compound (B) is at least one of rosin with an acid value of below 180(mgKOH/g) and a metal-free rosin derivative with an acid value of below 180 (mgKOH/g).