A POS terminal unit is provided which automatically notifies an operator about the presence of a customer waiting to make a purchase when a salesclerk is absent from the POS terminal unit. When an approach sensor 1 detects the approach of a customer to the POS terminal unit, a signal is transmitted to a control portion through a first detecting portion 3 and a buzzer is activated. An ID card identification sensor 2 is a non-contact type sensor capable of receiving data of an ID card 8 located within a predetermined space range, and sends the data of the ID card owned by the operator to a second detecting portion. After confirming whether or not the data received by the second detecting portion agrees with the pre-registered ID data registered in an ID information registration portion 9, the data is sent to the control portion 5. The control portion does not activate the buzzer 7 even when the control portion receives data about the customer's approach from the first detecting portion 3 if the operator is present near the POS terminal unit.