A main object of the present disclosure is to provide a structural member with a good balance between bending strength and lightweight property. The present disclosure achieves the object by providing a structural member comprising an edge portion T 1 and an edge portion T 2 opposing the edge portion T 1 in plan view in height direction (Z axis direction); when an axis direction connecting the edge portion T 1 and the edge portion T 2 is regarded as an X axis direction, the structural member includes, along the X axis direction, a region A including the edge portion T 1 , and a region B located on the edge portion T 2 side than the region A and including the edge portion T 2 ; in a cross-section perpendicular to the X axis direction, the region A includes a closed cross-section portion A whose outer rim shape is one closed cross-section A; and the region B includes a closed cross-section portion B satisfying a predetermined (i) or (ii).