This provides a vehicle body structure including: a lower panel made of resin, which has a lower wall that forms a lower portion of a floor portion, an outer front wall that is placed to extend from a vehicle body front end of the lower wall to an upper direction of a vehicle body, and an outer back wall that is placed to extend from a vehicle body backside end of the lower wall to the upper direction of the vehicle body; and an upper panel made of resin, which has upper walls that form an upper portion of the floor portion opposite to the lower wall, an inner front wall that is placed to extend from the vehicle body front ends of the upper walls to the upper direction of the vehicle body and joined to the outer front wall and consequently forms a closed cross-section shape that extends in a vehicle width direction while including both of left and right ends at an upper portion of the outer front wall, and an inner back wall that is placed to extend from the vehicle body backside ends of the upper walls and to the upper direction of the vehicle body and joined to the outer back wall and consequently forms a closed cross-section shape that extends in the vehicle width direction while including both of left and right ends at an upper portion of the outer back wall.