Lower vehicle body structure

A lower vehicle body structure includes a vehicle body floor having a bottom surface part, a floor tunnel bulging upwardly from the bottom surface part and extending in vehicle front-and-rear directions, side sills extending in the front-and-rear directions, hinge pillars extending upwardly from the side sills, first frames, lowered parts and second frames. Each first frame extends in the front-and-rear directions between the floor tunnel and a side sill. Each lowered part is provided to the bottom surface part between a first frame and a side sill so as to be lowered below a part where the floor and the side sills are joined. Each second frame extends to a first frame, obliquely rearwardly and inwardly from a side sill along an upper surface of the bottom surface part, and forms in a part including a lowered part a closed cross-section between the bottom surface part and a second frame.