A fuel inlet structure of a vehicle, the fuel inlet structure comprising: a vehicle body panel, a mounting aperture for inlet box mounting penetrating through the vehicle body panel; an inlet box attached to the vehicle body panel, the inlet box including: a box portion, the box portion being formed in a box shape and disposed such that a box opening thereof is oriented toward a cabin outer side, a penetrating hole being formed in a floor wall portion of the box portion, and a flange portion, the flange portion extending from a whole circumference of a peripheral edge of the box opening and being disposed along a peripheral edge portion of the mounting aperture of the vehicle body panel; and a seal portion, the seal portion being provided at a distal end side of the flange portion and disposed at the cabin outer side of the vehicle body panel, the seal portion forming a seal between the flange portion and the vehicle body panel along the whole circumference of the flange portion, wherein the seal portion includes: an inner seal portion provided in correspondence with the whole circumference of the flange portion, the inner seal portion being in contact with a region at a peripheral edge side of the mounting aperture of the vehicle body panel along the whole circumference of the flange portion; an outer seal portion provided in correspondence with the whole circumference of the flange portion, the outer seal portion being in contact with the vehicle body panel in a region further from the peripheral edge of the mounting aperture than the inner seal portion, the fuel inlet structure being characterised by further comprising: a drain portion for drainage being formed penetrating through a portion of a region of the outer seal portion that is disposed at a vehicle lower side relative to the inner seal portion; and a water catching portion, the water catching portion, in a portion of the whole circumference of the seal portion that is a lower portion in the vehicle vertical direction, projecting from a region between a proximal end portion of the inner seal portion and a proximal end portion of the outer seal portion to a region encompassing an area between the drain portion and the inner seal portion, the water-catching portion being configured to stop water that passes through the drain portion from a vehicle outer side. a vehicle body panel, a mounting aperture for inlet box mounting penetrating through the vehicle body panel; an inlet box attached to the vehicle body panel, the inlet box including: a box portion, the box portion being formed in a box shape and disposed such that a box opening thereof is oriented toward a cabin outer side, a penetrating hole being formed in a floor wall portion of the box portion, and a flange portion, the flange portion extending from a whole circumference of a peripheral edge of the box opening and being disposed along a peripheral edge portion of the mounting aperture of the vehicle body panel; and a box portion, the box portion being formed in a box shape and disposed such that a box opening thereof is oriented toward a cabin outer side, a penetrating hole being formed in a floor wall portion of the box portion, and a flange portion, the flange portion extending from a whole circumference of a peripheral edge of the box opening and being disposed along a peripheral edge portion of the mounting aperture of the vehicle body panel; and a seal portion, the seal portion being provided at a distal end side of the flange portion and disposed at the cabin outer side of the vehicle body panel, the seal portion forming a seal between the flange portion and the vehicle body panel along the whole circumference of the flange portion, wherein the seal portion includes: an inner seal portion provided in correspondence with the whole circumference of the flange portion, the inner seal portion being in contact with a region at a peripheral edge side of the mounting aperture of the vehicle body panel along the whole circumference of the flange portion; an outer seal portion provided in correspondence with the whole circumference of the flange portion, the outer seal portion being in contact with the vehicle body panel in a region further from the peripheral edge of the mounting aperture than the inner seal portion, an inner seal portion provided in correspondence with the whole circumference of the flange portion, the inner seal portion being in contact with a region at a peripheral edge side of the mounting aperture of the vehicle body panel along the whole circumference of the flange portion; an outer seal portion provided in correspondence with the whole circumference of the flange portion, the outer seal portion being in contact with the vehicle body panel in a region further from the peripheral edge of the mounting aperture than the inner seal portion, a drain portion for drainage being formed penetrating through a portion of a region of the outer seal portion that is disposed at a vehicle lower side relative to the inner seal portion; and a water catching portion, the water catching portion, in a portion of the whole circumference of the seal portion that is a lower portion in the vehicle vertical direction, projecting from a region between a proximal end portion of the inner seal portion and a proximal end portion of the outer seal portion to a region encompassing an area between the drain portion and the inner seal portion, the water-catching portion being configured to stop water that passes through the drain portion from a vehicle outer side.