A mobile communication apparatus includes a registration request part (47) requesting a correspondent node to make location registration, a BU list memory (45) keeping a list of the correspondent nodes which have made the location registration, a handover detection part (41) detecting the start of a handover, and a registration cancellation processing part (46) canceling the location registration of the correspondent nodes in the BU list, upon notification of start of handover by the handover detection part (41), thereby reducing loss of packets transmitted from the correspondent nodes during the handover, because the route optimization applied to the correspondent nodes registered in the BU list at the start of the handover is canceled by requesting the cancellation to the correspondent nodes.