A rotation unit of an image processor rotates at least any one of a securing unit for securing an object, an illumination unit for illuminating the object secured by the securing unit, and an image reading unit for reading an image of the object secured by the securing unit. A matching value calculation unit calculates the matching value for matching the image read by the image reading unit and the image in an image storing unit for storing images of objects previously read. A controller controls the rotation by the rotation unit based on the matching value calculated by the matching value calculation unit.