An operator number setting control unit 45 sets the number of contracted operators for a commissioned call center service in response to a request of a user. A log-in time collecting control unit 42 calculates the log-in time of the operator. A log-in time computing unit 43 adds respective log-in times for each user. A billed service charge computing device 44 calculates an amount of charge billed in accordance with the total sum of log-in time added for each user. A charge is calculated and billed as such for the amount of use of commissioned call center services in accordance with the usage pattern of users, thereby promoting the commissioning of call center services and making it possible to operate a call center system without a huge amount of capital investment.