To provide a composite material wing capable of remarkably reducing the number of parts and assembling man-hour and reducing cost.

A plurality of composite material intermediate beams 2 in which upper and lower surfaces of flanges 5, 6 form a partial shape of a wing surface are coupled so that surface shapes of the flanges 5, 6 may be smoothly continuous, the intermediate beams 2 molded into U-shapes in cross section by composite materials are arranged in the same direction so that a base end part external surface and an opening end internal surface may come into surface contact with the adjacent intermediate beams 2 and the adjacent intermediate beams each other are coupled by a fastener means 3.