NOVELTY - Manufacture of windmill blade involves drawing (S2) fiber bundle of multiple reinforced fibers from several bobbins, producing fibrous reinforcing sheet by arranging the fiber bundle of the multiple units from each bobbin, preparing resin-impregnated fiber sheet by impregnating (S6) non-solvent and liquid thermosetting resin into the fibrous reinforcing sheet, arranging (S8) resin-impregnated fiber sheet on a mold with the thermosetting resin, heat-hardening (S10) and molding the thermosetting resin of the resin-impregnated fiber sheet, and forming the windmill blade.    USE - Manufacture of windmill blade (claimed).    ADVANTAGE - The method enables the manufacture of windmill blade with thermosetting resin having excellent impregnatability and fluidity during molding, by simple and fast process. The occurrence of defects in the structural component of the windmill blade is suppressed.    DETAILED DESCRIPTION - Manufacture of windmill blade involves drawing fiber bundle of multiple reinforced fibers from several bobbins, producing fibrous reinforcing sheet from the fiber bundle of multiple units by arranging the fiber bundle of the multiple units from each bobbin and carrying out opening (S4) of fiber bundles, overlapping and adjoining the fiber-openings, preparing resin-impregnated fiber sheet comprising reinforced fibers and non-hardened thermosetting resin by impregnating non-solvent and liquid thermosetting resin into the fibrous reinforcing sheet, arranging resin-impregnated fiber sheet on a mold with the thermosetting resin in a non-hardened state, heat-hardening and molding the thermosetting resin of the resin-impregnated fiber sheet, and forming the windmill blade having one or more portions containing fiber-reinforced plastics.    DESCRIPTION OF DRAWING(S) - The drawing shows the flowchart explaining the manufacture of windmill blade.    Drawing fiber bundle from bobbins (S2)    Opening fiber bundles (S4)    Impregnating liquid thermosetting resin into fibrous reinforcing sheet (S6)    Arranging resin-impregnated fiber sheet on mold (S8)    Heat-hardening thermosetting resin (S10)