A method for making a windmill blade is provided, whereby problems with glue joints and with exposure of the workers to environmentally hazardous substances are avoided. This is effected by making the windmill blade in a closed mold with a mold core (3) inside mold parts (22, 48) for formation of a mold cavity (51), in which fiber material (45, 47) and core material (46) are placed. After applying vacuum to the mold cavity (51), matrix material (57) is injected via a filling pipe (29), which is placed at a downwardly oriented side edge of the blade during the filling. Hereby is established a flow front (61) which is used for indicating complete filling when this reaches the trailing edge of the blade and penetrates out through overflow apertures.