VEHICLE BODY CROSS MEMBER STRUCTURE

There is provided a vehicle body cross member structure. A floor panel configures a vehicle body floor. A pair of side members are provided at a lower surface-side of the floor panel and extend in a vehicle front-rear direction and respectively along both ends of the floor panel in a vehicle width direction. A cross member bridges between the pair of side members and supports the floor panel over the vehicle width direction. A cross-sectional surface of the cross member as seen in the vehicle width direction has a hat shape protruding downwardly from the floor panel. The cross member has a central area positioned at a center in the vehicle width direction and two outer extension areas extending further outwardly from both ends of the central area in the vehicle width direction and each having a part of which a protruding amount of the hat shape is larger than that of the central area. When seeing the cross member from below, two shape change lines which are starting points of a change in the protruding amount of the hat shape, are formed so as to be oblique relative to the vehicle front-rear direction and to be non-parallel with each other.