PURPOSE: To identify the kind of oil before starting oil feeding and prevent the intrusion of oil into a vapor suction pipe during oil feeding.

CONSTITUTION: An oil feed nozzle 3 connected at one end to an oil supply hose 5 is inserted at the other end into a supply opening 6a of a fuel tank 6 during oil feeding. By driving an air suction pump 19, the vapor in the tank 6 is sent through a vapor suction pipe 16 arranged along the oil supply hose 5 and then through pipes 17a and 17b into an underground tank 8. An oil kind detecting sensor 18 provided in a detecting pipe 17a detects the oil kind from the oil vapor pressure of the vapor supplied from the vapor suction pipe 16. A control device 12, when the kinds of the oil in the underground tank 8 and the tank 6 agree with each other, activates the pump 9 to perform either the first function of supplying the oil from the underground tank 8 to the oil feed tank 6 or the second function of supplying the oil without identifying the oil kind. During oil feeding, a switching valve 20 is switched to drive an air discharge pump 24 so as to send the air sucked from an air suction pipe 17c through the detecting pipe 17a and then through the vapor suction pipe 16 to clean the sensor 18 and the air is then discharged from a vapor suction opening 3b into the fuel tank 6.