This invention comprises acquiring information about connection time, information about an amount of transmitted and received data during the connection time and information about line speed during the connection time for a specific user, judging whether a utilization state of a specific user is in a predetermined state by using the information about the connection time, the information about the amount of the transmitted and received data and the information about the line speed, and sending a notification concerning the specific user to the specific user, or to a manager or the like, if it is judged that the utilization state of the specific user is in the predetermined state. Thus, a notification concerning a user having a low utilization degree can be made, and therefore, improvement of the utilization rate can be encouraged.