Abstract: An outgo time of first customers in a service providing store such as a restaurant is estimated and is notified to a second customer who made a reservation without time designation. Information relative to a usage amount of money of the first customers in a restaurant is obtained, and an accumulated usage amount of money per customer is calculated. Then, it is judged whether the accumulated usage amount of money per customer exceeds a predetermined reference amount of money. If a second customer makes a reservation for a reservation unit including the seat of the first customers and it is judged that the accumulated usage amount of money of the customer exceeds the predetermined reference amount of money, an outgo time of the first customers, which is obtained by adding a reference time to a time, is notified to the second customer. Thus, the second customer can go to the restaurant in view of the outgo time.