Abstract: This invention relates to a refueling nozzle that can be inserted easily into a filler opening in such a manner as to seal up the filler opening, securely engaging the nozzle and opening, and thereby prevent erroneous operation. Additionally, the refueling nozzle can automatically stop or start the refueling. The fuel discharge unit 3 comprises a fitting member 9 in the shape of a truncated cone such that the cross-sectional diameter gradually becomes smaller from a value larger than the inside diameter of the filler opening of a fuel tank. In the fitting member 9, a vapor passage 11 is formed to recover or discharge fuel vapor in the fuel tank. A fuel sensor 14 detects the presence of fuel and kind of fuel vapor present in the fuel tank through contact with the fuel vapor flowing through the vapor passage 11. A liquid level sensor 15 determines the surface level of fuel in the tank and whether the level of the fuel in the fuel tank has reached a predetermined level.