Fuel tank opening-closing device

A fuel tank opening-closing device that opens and closes a fuel passage for supplying fuel discharged by a fueling nozzle to a fuel tank, the fuel tank opening-closing device comprising:

• a tank opening forming member that includes (i) the fuel passage, (ii) a first opening forming member disposed in the fuel passage and having a first opening, and (iii) a second opening forming member disposed inside the fuel passage and in the fuel tank side and having the second opening,
• a first flap valve mechanism that includes a first opening-closing member for opening and closing the first opening, and
• a second flap valve mechanism that includes (i) a second opening-closing member for opening and closing the second opening and (ii) a gasket that seals between the second opening and the second opening-closing member,
• wherein the tank opening-closing member includes:
• an insertion passage forming member including (i) a passage forming main body for forming an insertion passage that connects the first opening and the second opening and for guiding the fueling nozzle from the first opening to the second opening, and (ii) a vent hole formed at an outer periphery of the first opening of the passage forming main body,
• a vent forming member having a gap with the insertion passage forming member at an outer periphery of the insertion passage forming member and disposed facing the vent hole, and
• a vent passage that connects the insertion passage with the outside through the gap and the vent hole.