PURPOSE: To provide a dogleg-shaped layer which is capable of transmitting a high tensile load by aligning plural high tensile strength fibers in one direction and forming a dogleg-shaped or a folded composite material layer which is joined using an appropriate joining medium without a twist over the entire length.

CONSTITUTION: A flexible beam 10 is formed by aligning high tensile filaments formed of a composite material in one direction and arranging two dogleg- shaped layers joined with a resin opposite to each other like a mirror image. In addition, the dogleg-shaped layer extends over the entire length of the beam 10 from a leg part 12 or is formed on a part of the length and reaches the entire length or a part of the two leg parts 12 arranged at mutually opposite positions in the diametral direction, passing through a forked center hub 18. Next, the dogleg-shaped layer made of resin-joined high tensile fibers endure a very high centrifugal load such as generated by the rotor of a helicopter during operating. This load is transferred from one of the leg parts 12 of the beam 10 to the other leg 12 positioned opposingly in the diametral direction to distribute the load.