A fuel tank capable of attaching functional parts and tubes in an interior thereof. In a fuel tank for a motor vehicle, which is formed by blow molding for attachment of a built-in part in an interior thereof, and of which an outer wall composed of a synthetic resin has an opening, a functional part adapted to discharge fluid from the interior of the fuel tank or feed fluid therein is attached to the built-in part, a tube adapted to discharge fluid from the interior of the fuel tank or feed fluid therein is connected to the functional part, and a tube connector is attached to an end of the tube. A temporal holding connector is formed integrally with the built-in part, the tube connector is attached to the temporal holding connector, and after blow molding, the tube connector is detached from the temporal holding connector and is attached to a tank cap adapted to close the opening of the fuel tank.