The blade includes a current part (1) having an aerodynamic profile enclosing a spar (7) and extending from blade tip (4) to a blade root (3) provided with a pitch sleeve (21), through which twisting arm (6) passes and protrudes beyond blade root (3), and having a first part of a bundle (5) of superimposed and elongated metal strips, current part (1) including a block (13) based on synthetic material molded in form in a single piece around spar (7), and a second part of bundle (5) extending in line with the first part forming the twisting arm (6) and cooperating with the anchoring devices (14, 17) of the block (13) based on synthetic material around the spar (7).