An article distinguishing system characterized by comprising: a storage unit configured to store exterior image data, which is data of an exterior image of an article, in association with identification information of the article; an identification information acquisition unit configured to acquire identification information of a target article, which is an article to be subjected to distinguishing; an image capture unit configured to capture an image of an exterior of the target article; a determination unit configured to derive a degree of matching between a captured image of the target article captured by the image capture unit and the exterior image data stored in the storage unit in association with the identification information acquired by the identification information acquisition unit, and determine whether or not the current state is a normal state in which the exterior image data for which the degree of matching is a determination threshold value or more is present; and a learning processing unit configured to execute learning processing if it has been determined by the determination unit that the current state is not the normal state, wherein the learning processing is processing for storing data of the captured image as new said exterior image data in the storage unit in association with the identification information acquired by the identification information acquisition unit, the storage unit stores a specified number, which is two or more, of pieces of the exterior image data in association with one piece of identification information in sequence starting from the exterior image data that was stored in the storage unit most recently, and in executing the learning processing, when the specified number of pieces of the exterior image data have already been stored in the storage unit in association with the identification information acquired by the identification information acquisition unit, the learning processing unit deletes from the storage unit the exterior image data that was stored in the storage unit at the earliest time among the specified number of pieces of exterior image data, and stores the new exterior image data in the storage unit. a storage unit configured to store exterior image data, which is data of an exterior image of an article, in association with identification information of the article; an identification information acquisition unit configured to acquire identification information of a target article, which is an article to be subjected to distinguishing; an image capture unit configured to capture an image of an exterior of the target article; a determination unit configured to derive a degree of matching between a captured image of the target article captured by the image capture unit and the exterior image data stored in the storage unit in association with the identification information acquired by the identification information acquisition unit, and determine whether or not the current state is a normal state in which the exterior image data for which the degree of matching is a determination threshold value or more is present; and a learning processing unit configured to execute learning processing if it has been determined by the determination unit that the current state is not the normal state, wherein the learning processing is processing for storing data of the captured image as new said exterior image data in the storage unit in association with the identification information acquired by the identification information acquisition unit, the storage unit stores a specified number, which is two or more, of pieces of the exterior image data in association with one piece of identification information in sequence starting from the exterior image data that was stored in the storage unit most recently, and in executing the learning processing, when the specified number of pieces of the exterior image data have already been stored in the storage unit in association with the identification information acquired by the identification information acquisition unit, the learning processing unit deletes from the storage unit the exterior image data that was stored in the storage unit at the earliest time among the specified number of pieces of exterior image data, and stores the new exterior image data in the storage unit.