<p>A extrusion structural angle comprising a material consisting of extrusion structural angle of aluminum alloy that is provided with a lateral rib (44) coupling two longitudinal walls in addition to a part forming a bottom face part (43) and a part forming at least two longitudinal walls (41, 42) is used as a material, characterized in that a component lower end supporting part is formed between the two longitudinal walls or at the bottom face part by cutting off the lateral rib partially. Preferably, the gap between two longitudinal walls from where the lateral rib is cut off is varied gradually.</p>
