LOWER VEHICLE BODY STRUCTURE

A lower vehicle body structure is provided, which includes a vehicle body floor having a bottom surface part, a floor tunnel bulging upwardly from the bottom surface part of the vehicle body floor and extending in vehicle front-and-rear directions, a power transmission mechanism disposed inside the floor tunnel, a mount member supporting the power transmission mechanism from below, and seat rails disposed on the vehicle body floor and slidably supporting seats from below. The mount member and the seat rails are jointly fastened to the vehicle body floor.