A vehicle body lower structure includes a battery pack, side sills, and a battery side frame that extends in a forward/rearward direction between the side sills and the battery pack and that is configured to support the battery pack, the battery side frame has a first attachment member fixed to the side sills, and a second attachment member that is coupled to the battery pack and that constitutes a closed cross section between the first attachment member and the battery pack, and the first attachment member has an outer fixing point fixed to the side sills and an inner fixing point fixed to a wall that constitutes a closed cross section of the second attachment member.