An alignment device comprising a tray including a transparent bottom plate for placing granular materials on a reading surface of an image reading device such as a scanner, and a removable alignment plate fit from an upper direction to the bottom plate of the tray, the tray further including: one or a plurality of nontransparent backgrounds standing perpendicular to the bottom plate to a height higher than a thickness of the granular materials, and one or a plurality of reflective elements (10A, 10B) arranged at predetermined intervals in parallel with the backgrounds; and the alignment plate further including: a protruded section for covering the backgrounds, protruded sections (17, 18) for covering the reflective elements (10A, 10B) disposed in parallel with the protruded section for the background, and a plurality of holes having a shape corresponding to an shape of the granular materials, the plurality of holes being arranged in such a way, that the granular materials being poured into the holes of the alignment plate fit to the bottom plate so that the granular materials are placed in orderly aligned manner on the bottom plate including the area between the background and the reflective elements (10A, 10B), wherein when the granular materials are placed between the background and the reflective elements (10A, 10B) and the alignment plate is removed, light including information about the side view of the granular materials placed between the background and the reflective elements (10A, 10B) is bent and guided such that it is directed to an optical axis of an imaging means of the image reading device, so that not only planar images of the granular materials but also a side view image of the granular materials placed between the background and the reflective elements (10A, 10B) can be received via the imaging means. a tray including a transparent bottom plate for placing granular materials on a reading surface of an image reading device such as a scanner, and a removable alignment plate fit from an upper direction to the bottom plate of the tray, the tray further including: one or a plurality of nontransparent backgrounds standing perpendicular to the bottom plate to a height higher than a thickness of the granular materials, and one or a plurality of reflective elements (10A, 10B) arranged at predetermined intervals in parallel with the backgrounds; and the alignment plate further including: a protruded section for covering the backgrounds, protruded sections (17, 18) for covering the reflective elements (10A, 10B) disposed in parallel with the protruded section for the background, and a plurality of holes having a shape corresponding to an shape of the granular materials, the plurality of holes being arranged in such a way, that the granular materials being poured into the holes of the alignment plate fit to the bottom plate so that the granular materials are placed in orderly aligned manner on the bottom plate including the area between the background and the reflective elements (10A, 10B), wherein when the granular materials are placed between the background and the reflective elements (10A, 10B) and the alignment plate is removed, light including information about the side view of the granular materials placed between the background and the reflective elements (10A, 10B) is bent and guided such that it is directed to an optical axis of an imaging means of the image reading device, so that not only planar images of the granular materials but also a side view image of the granular materials placed between the background and the reflective elements (10A, 10B) can be received via the imaging means. a protruded section for covering the backgrounds, protruded sections (17, 18) for covering the reflective elements (10A, 10B) disposed in parallel with the protruded section for the background, and a plurality of holes having a shape corresponding to an shape of the granular materials, the plurality of holes being arranged in such a way, that the granular materials being poured into the holes of the alignment plate fit to the bottom plate so that the granular materials are placed in orderly aligned manner on the bottom plate including the area between the background and the reflective elements (10A, 10B), wherein when the granular materials are placed between the background and the reflective elements (10A, 10B) and the alignment plate is removed, light including information about the side view of the granular materials placed between the background and the reflective elements (10A, 10B) is bent and guided such that it is directed to an optical axis of an imaging means of the image reading device, so that not only planar images of the granular materials but also a side view image of the granular materials placed between the background and the reflective elements (10A, 10B) can be received via the imaging means.