To prevent the deterioration of the performance of a TCP due to a packet to be transferred according to the transfer request of a packet to be transmitted from a mobile terminal after hand-over.

In a mobile terminal 100, whether or not a replay is returned to a packet transmission origin is decided according to a threshold to be decided based on the number of packets which have not been correctly received during hand-over, the number of packets which can be held in a network, and a using congestion control algorithm. Then, when it is judged that it is necessary to return the reply to the packet transmission origin, the number of packets to be returned to the packet transmission origin is calculated. Thus, it is possible to solve the problem that the through-put of the TCP is deteriorated due to the packets transferred from a movement origin AR 200a after hand-over.