A vehicle battery-carrying floor structure that includes: a bottom plate member that has a plurality of unit members that are arranged in a vehicle body forward and rearward direction and that are joined by joining opposing joint portions, each unit member having a flat plate portion that extends in a vehicle width direction and that has the joint portions formed at an end portion facing the vehicle body forward direction and at an end portion facing the vehicle body rear direction and a partition portion that is disposed upright so as to extend in the vehicle width direction on an upper surface of the plate portion; and side plate members that are provided on an upper surface of the bottom plate member on outer sides in the vehicle width direction of the partition portions and form, with the partition portions, regions that hold battery packs.