[Problem] To provide a curable organopolysiloxane antifouling composite coating film obtained by using a urethane resin anticorrosive coating film excellent in curability instead of one or two organopolysiloxane intermediate coating film layers (Tie Coats) to layer an organopolysiloxane antifouling coating film excellent in both interlayer adhesiveness with the anticorrosive coating film and antifouling performance; and an antifouling substrate coated with the composite coating film.[Solution] An antifouling composite coating film, comprising a laminated urethane resin anticorrosive coating film and antifouling coating film, (I) the urethane resin anticorrosive coating film being formed from an anticorrosive paint composition comprising a main agent selected from the group consisting of polyols and glycidyl ethers, and an isocyanate curing agent, (II) the antifouling coating film being formed from a curable polysiloxane composition comprising specific components (a), (b), and (c).