PURPOSE: To avoid irregularities such as bridging and folds on a concave-facing surface by placing a rigid mold tool on one side of a composite material body in a region and on the other side of the composite material body in another region so as to apply pressure via a pressure membrane to the curved composite material body.

CONSTITUTION: A first rigid mold 47 is disposed in an inside surface of a cylindrical body 22, a third rigid mold 56 which replaces a second rigid mold for debulking is disposed so that a flat surface 57 thereof fits against the inwardly facing surface of a flange 24, and the convex surface 58 fits into the concave curvature of the corner between the body 22 and the flange 24, where the radius of curvature is in the region on the side of a body 20. The inclined surfaces 66, 68 permit the adjacent pressure membranes to be brought into a smooth, unwrinkled contact with the surface of the part 20. At a crossover point 64, there is a smooth transition of the mold and the pressure membrane from one side of the part 20 to the other side. The corner between the cylindrical body and the flange is smooth, regular, and without folds and bridging. The surfaces are made to particular dimensional specifications of the concave and flat surfaces.