The method of forming reinforced fiber base material is provided with: arranging, on the mold having a projection with a upper surface, a platform that is adjacent to the projection and has a flat upper surface at the same height as the upper surface of the projection; forming the laminate by placing reinforced fiber base material in layers on the upper surface of the projection; placing an end of the laminate in the width direction extending out of the upper surface of the projection, on the upper surface of the platform, with the end of the laminate in the width direction sandwiched in a vertical direction by a pair of the films of which outer ends in the width direction are fixed to each other; and removing the platform and pulling out the pair of the films while shaping the laminate along the projection.