A method of manufacturing a structure is provided in which a burr portion can be more reliably cut. In a burr portion shaping step, the burr portion is sucked to an engaging portion by a suction part to shape the burr portion along the engaging portion, and in a cutting step, ae movable portion is moved relative to first and second split molds with the burr portion being shaped along the engaging portion, thereby the burr portion is cut from a molded main body along a cutting line.