A network selection control method is a method for selecting, from a E-UTRAN and a WLAN, an access network in which a traffic of a UE 100 is transmitted and received. The network selection control method comprises the steps of: transmitting, by a cell #1 in the E-UTRAN, offload control information to a UE 100-1 that exists in the cell #1, the offload control information being for requesting switching of an access network in which the traffic of the UE 100-1 is transmitted and received, to the WLAN; and transmitting, by a cell #2 neighboring the cell #1 in the E-UTRAN, to a UE 100-2 that exists in the cell #2, neighboring cell offload information indicating that the offload control information is transmitted in the cell #1.