PURPOSE: To avoid the strain, the warp and the like within the base component and at the same time enabling a uniform distribution of the impregnated resin, by shifting the base component on the belt to wrap it in sequence among the belts and then hardening the resin while bending it into an arc shape.

CONSTITUTION: Thermosetting resin 21 is impregnated into tape-type base component 1 made of the galss fiber woven fabric or the like in resin impregnating bath 2. Then component 1 is folded sequentially in the direction of length by belt folding device 4 while being shifted on belt 3 and then wrapped with belt 3. Component 1 in such condition is then bent into an arc shape by bending formation device 6, and at the same time resin 21 is hardened. After this, belt 3 is returned to the original state is sequence by belt releasing device 5, and then component 1 is released from belt 3. In this way, no tensile stress is applied to component 1, causing no internal strain. Thus the warp, the bend and the twist can be prevented for component 1 to enable a uniform distribution of the resin.