<p>The fuel tank structure includes: a fuel tank (14) that is configured to contain fuel inside; a liquid level detection sensor (26L) arranged in a vertical orientation inside the fuel tank and configured such that a capacitance of the liquid level detection sensor varies on the basis of a contact range in which the fuel is in contact with the liquid level detection sensor; a tubular element (38) extending vertically while laterally surrounding the liquid level detection sensor and configured to allow the fuel to enter from a lower portion of the tubular element to an inside of the tubular element and to exit from the inside to the lower portion; and a fuel storage member (58) that communicates with the inside of the tubular element (38) and the inside of the fuel tank (14) through a fuel input/output port (56) and configured to store the fuel inside the fuel tank.</p>