Fuel tank fueling device

A fuel tank fueling device (10) for feeding fuel through the fuel passage of an inlet pipe into a tank main body is provided. The fueling device is easier to manipulate when the fuel cap is opened and closed, and also has better fuel tank sealing properties against the outside air. The fueling device includes a handle (43) provided on a casing main body (20), operated to open and close the fuel passage; a sealing component (GS) interposed between the casing main body and the seat surface of the fuel inlet pipe; a spring (98) disposed so as to urge the sealing component against the seat surface; and a cam mechanism (80,90) whereby the operating force of the handle in the closing direction is converted via the spring into the sealing force of the sealing component pressing against the seat surface.