To provide a method to make reinforcement of an inclined rising part in the folded plates effectively, thereby making it possible to provide such a folded plate that is lighter in weight and nigger in pitch.

In such a folded plate for construction use made as follows; a long steel strip is folded in a lengthy direction to provide a bottom plate section in the center and further inclined rising sections on both sides of the same bottom plate section. In addition, a top section is formed on the flanges of the same rising section. In the same rising section, a continuous wavelike rib in the lengthy direction or such an inclined line like rib that repeatedly distributes while changing its direction is formed.