A commodity registration supporting device according to an embodiment includes a receiver, an acquiring section, a first detecting section, an adding section, and an output section. The receiver receives an electromagnetic wave transmitted from a first transmitter provided in a display place where a commodity is displayed. The acquiring section acquires, from the electromagnetic wave received by the receiver, identification information of the commodity displayed in the display place where the first transmitter that transmits the electromagnetic wave is provided. The first detecting section detects a first act of a purchaser taking out the commodity from the display place and storing the commodity in a storage body. The adding section adds, if first act is detected by the first detecting section, the commodity identified by the identification information acquired by the acquiring section to a list. The output section outputs the list.