An outer energy absorbing member and an inner energy absorbing member are mounted on a lower surface side of a vehicle bottom part. The outer energy absorbing member and the inner energy absorbing member are arranged adjacent and in parallel to each other in a vehicle width direction. A recessed engagement part is formed in a side end part of the outer energy absorbing member on an inner side in the vehicle width direction, and a projecting engagement part is formed in a side end part of the inner energy absorbing member on an outer side in the vehicle width direction. The recessed engagement part and the projecting engagement part are engaged with each other at a time of side impact.
