Abstract: A method for manufacturing at least one impregnated fibrous material including a fibrous material made of continuous fibers and at least one thermoplastic polymer, the method including a step of impregnating the at least one fibrous material in a pultrusion head by injecting a reactive composition in the melt state including at least one precursor of the thermoplastic polymer in the presence of the fibrous material, the at least one fibrous material on entry into the pultrusion head being divided in its thickness into layers, with each layer circulating in its own channel within the pultrusion head, the reactive composition being injected into each channel and/or between the layers when they are recombined at the exit from each channel, the channel being heated, in which the precursors of the thermoplastic polymer are at least partly polymerized.