Provided is a fuel system comprising a fuel vessel, molded parts for a fuel and/or a tube for a fuel in which bodies are constituted from at least one of a thermoplastic resin and a synthetic rubber, wherein a coating layer is formed on the surfaces in at least one side of the insides and the outsides of the fuel vessel body, the molded part bodies for a fuel and/or the tube body for a fuel or at least one of connected parts in these bodies; the above coating layer is formed by curing a polyurethane resin composition comprising an active hydrogen-containing compound (A) and an organic polyisocyanate compound (B); and the above coating layer has a gasoline permeability coefficient of 2 g·mm/m2·day or less at 23° C. and a relative humidity of 60% RH. The above coating layer is excellent in a permeation-preventing performance against an automobile fuel (gasoline barrier property), an adhesion property between fuel vessel body and molding parts or tube, a heat resistance and an impact resistance, a flexibility, a bending resistance, etc., then a fuel vessel, molded parts for a fuel and a tube for a fuel which have excellent performances are obtained.