To provide a device that prevents erroneous payments during use, reduces introduction costs and initial costs, enables grasping of sales information based on cash payments, and allows a cashless
payment function to be easily and inexpensively introduced.SOLUTION: A retrofit unit 1 that is mounted in an add-on manner to a device capable of
cash payment to add a cashless
payment function includes a code display portion to which a printed sticker displaying a two-dimensional code symbol is attached. When a user terminal 6 reads the code symbol,
pairing by short-range
wireless communication is performed. A cashless
control unit 2 transmits
payment information including a payment amount to the user terminal, and a payment request is made to a payment
server 5 via a device use support
server 7 by a device application 6 on the user terminal. When normal completion of payment is transmitted to a short-range
wireless communication unit 4 via the user terminal, the cashless
control unit outputs a payment completion
signal to a cashless output unit 3 with the same communication specifications as those used for confirmation of cash
receipt by cash
receipt confirmation units 81, 82, thereby enabling use of the device.SELECTED DRAWING: Figure 2