A sealing member is provided at an inner periphery sealing portion thereof with an inner tube portion arranged to be moved toward a fuel feed port inner side with the insertion of a fuel feed nozzle and to be moved toward a fuel feed port opening side with the removal of the fuel feed nozzle. The inner tube portion is provided, at the outer periphery of the end thereof at the fuel feed port opening side, with a tapered tube portion extending toward an outer tube portion side. With the movement of the inner tube portion toward the fuel feed port opening side, the inner tube portion is increased in inner diameter such that the increased inner diameter is greater than the outer diameter of the fuel feed nozzle, and with the movement of the inner tube portion toward the fuel feed port inner side, the inner tube portion is reduced in inner diameter, causing the same to stick fast to the outer periphery of the fuel feed nozzle.