1. An enclosure inspection sorting method, comprising: providing an enclosure inspection device having an X-ray inspecting device, a thickness detector, and an inspection device; using the thickness detector to determine whether or not an inspection object is thicker than a predetermined thickness while conveying the inspection object; radiating X-rays, using an X-ray radiator, onto the inspection object to determine whether or not a suspected object is enclosed in the inspection object from the obtained X-ray image and to detect a coordinate position of the suspected object in the inspection object; using the inspection device to radiate a terahertz wave or a millimeter wave onto the suspected object in the inspection object which has been determined to be thinner than the predetermined thickness and determined to have the suspected object enclosed therein on the basis of the coordinate position, and determining whether or not the suspected object is a predetermined object by detecting a scattered wave, a transmitted wave, or a reflected wave of the terahertz wave or millimeter wave; and sorting each inspection object into one of an inspection object which is determined to be thicker than the predetermined thickness, an inspection object which is determined to be thinner than the predetermined thickness and to have a predetermined object enclosed therein, and an inspection object which is determined to be thinner than the predetermined thickness and not to have the predetermined object enclosed therein.