A technology is provided that easily acquires the location where an article is placed and then moves to that location, even in cases where the article was originally placed in a location shielded from GPS radio wave, and subsequently moved to another location. Marks and RFID tags are affixed to a movable tray. A transfer robot includes a camera, a reader, and a sensor. The transfer robot detects the tray location from the location of a region in an image photographed by the camera that matches mark information. Furthermore, the reader in the transfer robot detects the tray location from the intensity of a radio wave whose information, when read, matches an ID retained in the RFID tag. The transfer robot moves with the camera and the reader, detecting the tray that is the target destination.