To solve the problem that a refueling nozzle for a different oil kind is inserted into an oil supply opening of a fuel tank.

The refueling nozzle 10 includes a discharging pipe 20, a nozzle body 30, and a nozzle lever 40. The nozzle body 30 has a valve mechanism (main valve) opened by the operation of the nozzle lever 40 and an automatic valve closing mechanism that opens the main valve when air introduction from a liquid surface detection hole 50 arranged at the tip of the discharging pipe 20 is shut off. A cylindrical member 70 is arranged at the outer circumference of the tip 22 of the discharging pipe 20. The end 76 at the downstream side of the cylindrical member 70 has an outer diameter D that is larger than the minimum inner diameter D2 of an erroneous insertion prevention part 92 arranged at the oil supply opening 90 of a fuel tank for gasoline. Therefore, when supplying oil into the fuel tank for gasoline using the refueling nozzle 10 for gas oil, the end of the cylindrical member 70 comes into contact with the erroneous insertion prevention part 92 formed at the inner wall of the oil supply opening 90, so that insertion is prevented.