PURPOSE: To obtain the titled formings excellent in strength and precission by a method wherein continuous fibers are impregnated with resin, then, said resin is aged, the fibers are wound about winding cores and a reinforcing plate which are set to the product size, stretched, held between forming forces hardened and formed at the normal temperature or by heating.

CONSTITUTION: The continuous fibers 2 are introduced into the impregnating tank 3 and impregnated with resin, then wound about the roll 9 and aged. Then, the aged prepreg 10 obtained is wound about winding cores 5a, 5b and the reinforcing plate 7 which are set respectively to the interval of the product size, and stretched. Then, as it is held between forming forces 8 it is hardened at the normal temperature or by heating to obtain the desired formed product.