A domain managing device adapted to conduct a protocol operation to implement local mobility of a mobile terminal having a plurality of interfaces on a network side, and that can be disposed in a communication system including a mobility management domain formed therein, the domain managing device managing a packet transfer path to the mobile terminal that connects with the mobility management domain, and keeping association information that associates the mobile terminal with an edge device with which the mobile terminal currently connects, the edge device being disposed at an edge on a terminal side of an access network of the mobility management domain, the domain managing device comprising: reception means that receives from a first edge device a message notifying that the mobile terminal tries to connect with the first edge device; association information keeping means that keeps the association information; check means that, when the reception means receives the message, refers to the association information kept by the association information keeping means so as to check whether the association information includes association information of the mobile terminal that tries to connect with the first edge device (11 a) or not; characterized in that inquiry means that, if the check means understands that the association information of the mobile terminal is included, makes an inquiry to a second edge device (11 b) associated using the association information of the mobile terminal to inquire whether connection with the mobile terminal is valid or not; and information keeping control means that, if it is judged as a result of the inquiry by the inquiry means that the connection with the mobile terminal is valid, makes the association information keeping means keep association information associating the mobile terminal with both of the first and the second edge devices (11 a, 11 b), and if it is judged the connection with the mobile terminal is not valid, deletes association information associating the mobile terminal with the second edge device from the association information keeping means, while making the association information keeping means keep association information associating the mobile terminal with the first edge device. reception means that receives from a first edge device a message notifying that the mobile terminal tries to connect with the first edge device; association information keeping means that keeps the association information; check means that, when the reception means receives the message, refers to the association information kept by the association information keeping means so as to check whether the association information includes association information of the mobile terminal that tries to connect with the first edge device (11 a) or not; characterized in that inquiry means that, if the check means understands that the association information of the mobile terminal is included, makes an inquiry to a second edge device (11 b) associated using the association information of the mobile terminal to inquire whether connection with the mobile terminal is valid or not; and information keeping control means that, if it is judged as a result of the inquiry by the inquiry means that the connection with the mobile terminal is valid, makes the association information keeping means keep association information associating the mobile terminal with both of the first and the second edge devices (11 a, 11 b), and if it is judged the connection with the mobile terminal is not valid, deletes association information associating the mobile terminal with the second edge device from the association information keeping means, while making the association information keeping means keep association information associating the mobile terminal with the first edge device.