A coating layer comprising: a layer prepared by curing 100 parts by mass in total of a film-forming agent containing: 3 to 45 parts by mass of a polyorganosiloxane (a-1) having at least one hydrolyzable functional group in its molecule; 0.05 to 5 parts by mass of a curing catalyst (a-2); and 50 to 96.95 parts by mass of an organic solvent (a-3) comprising a saturated hydrocarbon solvent having 8 to 15 carbon atoms and an aromatic hydrocarbon solvent having 8 to 15 carbon atoms at a mass ratio of the saturated hydrocarbon solvent to the aromatic hydrocarbon solvent of 100/0 to 50/50, and a layer prepared by solidifying 100 parts by mass in total of a finish treatment agent containing: 0.05 to 15 parts by mass of a polyorganosiloxane (b-1) having at least one pendant amino group; 0.01 to 10 parts by mass of a polyorganosiloxane (b-2) having two or more terminal amino groups; 1 to 20 parts by mass, in terms of the solid content, of a silicone resin emulsion (b-3) emulsified with a nonionic or anionic surfactant; 0.1 to 25 parts by mass of a hydrophilic group-containing organic solvent (b-4); and 30 to 98.84 parts by mass of water (b-5), wherein the layer is disposed on a base material side, and the layer is disposed on a surface side. a layer prepared by curing 100 parts by mass in total of a film-forming agent containing: 3 to 45 parts by mass of a polyorganosiloxane (a-1) having at least one hydrolyzable functional group in its molecule; 0.05 to 5 parts by mass of a curing catalyst (a-2); and 50 to 96.95 parts by mass of an organic solvent (a-3) comprising a saturated hydrocarbon solvent having 8 to 15 carbon atoms and an aromatic hydrocarbon solvent having 8 to 15 carbon atoms at a mass ratio of the saturated hydrocarbon solvent to the aromatic hydrocarbon solvent of 100/0 to 50/50, and 3 to 45 parts by mass of a polyorganosiloxane (a-1) having at least one hydrolyzable functional group in its molecule; 0.05 to 5 parts by mass of a curing catalyst (a-2); and 50 to 96.95 parts by mass of an organic solvent (a-3) comprising a saturated hydrocarbon solvent having 8 to 15 carbon atoms and an aromatic hydrocarbon solvent having 8 to 15 carbon atoms at a mass ratio of the saturated hydrocarbon solvent to the aromatic hydrocarbon solvent of 100/0 to 50/50, and a layer prepared by solidifying 100 parts by mass in total of a finish treatment agent containing: 0.05 to 15 parts by mass of a polyorganosiloxane (b-1) having at least one pendant amino group; 0.01 to 10 parts by mass of a polyorganosiloxane (b-2) having two or more terminal amino groups; 1 to 20 parts by mass, in terms of the solid content, of a silicone resin emulsion (b-3) emulsified with a nonionic or anionic surfactant; 0.1 to 25 parts by mass of a hydrophilic group-containing organic solvent (b-4); and 30 to 98.84 parts by mass of water (b-5), wherein the layer is disposed on a base material side, and the layer is disposed on a surface side. 0.05 to 15 parts by mass of a polyorganosiloxane (b-1) having at least one pendant amino group; 0.01 to 10 parts by mass of a polyorganosiloxane (b-2) having two or more terminal amino groups; 1 to 20 parts by mass, in terms of the solid content, of a silicone resin emulsion (b-3) emulsified with a nonionic or anionic surfactant; 0.1 to 25 parts by mass of a hydrophilic group-containing organic solvent (b-4); and 30 to 98.84 parts by mass of water (b-5), wherein the layer is disposed on a base material side, and the layer is disposed on a surface side.