VEHICLE LOWER PORTION STRUCTURE

A vehicle lower portion structure includes: a seat cushion that is provided in a cabin and that includes a sitting area in which an occupant sits; a seat base that is provided on a vehicle lower side of the seat cushion, with at least part of the seat base being disposed under the sitting area, and that supports the seat cushion from below; and a reinforcement member that is provided between the seat cushion and the seat base, that is supported by an upper surface of a front portion of the seat base, and that extends along a vehicle width direction.