A main suction, that is a portion of a fuel feed-out pipe, and a bent portion, that is a lowermost portion formed at a return pipe, are both disposed within a fuel tank, positioned lower than a lowest liquid surface within a reserve cup, and can always be maintained in a state of existing within fuel. A fuel expelling port of a jet pump is positioned higher than a highest liquid surface at the reserve cup, and is always positioned higher than fuel within the reserve cup. As a result, a fuel tank structure in which suppression of flowing-out of fuel from the return pipe and the like, an improvement in the fuel transferring performance of the jet pump, and suppression of backward flowing of fuel through a transfer pipe, can all be realized is obtained.