A policy and charging rules function (PCRF) stores a policy rule management table in which a policy rule corresponding to a combination of contract information and a device type is registered and a hierarchical management table in which user information including contract information of a user and information on the device are managed in association with each other, acquires the device type serving as an application target of the policy rule, and a device ID assigned to the device, determines the policy rule according to the acquired device type and the contract information of the user, and instructs a deep packet inspection (DPI) to apply the determined policy rule to the device corresponding to the acquired device ID. The DPI acquires the device ID, and applies the policy rule to communication from the device corresponding to a device ID assigned to the device, and performs control.