This invention aims to provide a technique that, in wireless network environments, enables the Manager to collect network management information (MIB data in the case of SNMP based network management), which the Agent has stored during periods of disconnection, after connectivity to the mobile nodes has recovered. In a wireless network environment, the Agent (201) has a unit for storing the management information related to network devices with appropriate label information, while the Manager (101) has a unit for sending the Agent a request for a label-specified data, and getting the data which the Agent has stored in Management Information Store 207. The above unit enables the Manager (101) to seamlessly collect the information pertaining to the period of disconnection, which the Agent (201) has stored in Management Information Store 207, after detecting recovery of the connectivity.