To provide structure shape material for construction of floor joist material and the like which is easy in manufacture and whose cost can be reduced by folding both the ends of the two-layer-like shape material of cross section H-shape formed of a metal plate up to a prescribed height position and drawing processing and bottom- raising them.

With regard to H-shape material 1 which is floor joist material, a wide and thin metal plate is gradually molded into a circular pipe through a forming roll group so that both edge parts are mutually approached at a just above position. Next, both the edge parts are butt-welded to form the cross section circular pipe. The circular pipe outer face of the outside rise part of the welded part is cut in a same face, and then the circular pipe is made an angular pipe. The angular pipe is gradually molded into cross section H-shape through a sizing roll group, the whole shape is made a double layer to mutually be adhered. Bending and drawing by press- forming or roll forming are performed on both the ends 5, 5 of the H-shaped material 1, and bottom-raised ends 6, 6 in which a lower flange side is bottom-raised up to a prescribed height position are formed. Thereby the cost can be reduced, and sufficient strength can be secured.