The present invention is designed such that a new SGSN receives a location update message from a terminal (1) having moved from the management area of an old SGSN to the management area of the new SGSN, and the new SGSN having received the location update message sends a GTPv2 signal for getting communication path information corresponding to GTPv2, to the old SGSN. The old SGSN, upon receiving the GTPv2 signal, if holding communication path information of to GTPv1 as a logical communication path established for the terminal (1), sends, as a response, a GTPv2 signal in which the communication path information by GTPv1 is set in an additional parameter 24, to the new SGSN.