A mobile communication system includes a management agent, server, and temporary server. The management agent manages the destination of a mobile node. The server serves as a communication partner of the mobile node. The temporary server has a network function equivalent to that of the server. The management agent includes a position registration unit which registers position information of the destination of the mobile node when the mobile node moves, and a server function relocation unit which sets the temporary server as the communication partner of the mobile node instead of the server. A management agent apparatus and server function moving method are also disclosed.