When a customer picks up a commodity at a store aisles and operates a tag device, a PLU code of the commodity is transmitted from the tag device to a weight-scale apparatus. The terminal device is provided corresponding to each commodity. The weight-scale apparatus upon receiving the PLU code increments a counter value (prepared per commodity) in only one step, and displays a commodity icon corresponding to the PLU code on a liquid-crystal touch panel. The counter value increments every time the PLU code is received. The weight-scale apparatus subsequent to weighing issues a label and decrement only a step of the counter value. The icon corresponding to the counter value continues to be displayed unless the counter value does not indicate “0 (zero)”. The icon is erased when the counter value indicates “0 (zero)”. This results in providing superior operations in weighing and selecting various types of commodities, displayed at the store aisles, that are objects to be weighed.