Provided is a vehicle body structure which can improve collision performance. The sub-side member 3 has a deformation cooperative movement portion 7 whose strength is made lower than the deformation suppressing portion 8 on the rear side, at a position ahead of a power unit EG. The sub-side member 3 easily deforms at a position ahead of the power unit EG when the load is applied. The sub-side member 3 can deform in synchronization with the deformation of the front side member 2, in a region ahead of the power unit EG with high strength and a relatively small number of disposition parts. Accordingly, the sub-side member 3 can absorb the load efficiently in cooperative movement with the front side member 2. Additionally, the sub-side member 3 is constructed so as to have a higher strength than the deformation cooperative movement portion 7, on the rear side of the deformation cooperative movement portion 7. Accordingly, the sub-side member 3 sufficiently transmits the load to a rear frame structure structure. Thereby, the load is distributed to the front side member 2 and the sub-side member 3.