Disclosed is a method of easily and reliably setting cell information in a control-plane processing device and a user-plane processing device in a radio access network, wherein the radio access network is provided with a radio network controller, which is divided into a control-plane processing device and a user-plane processing device. The control-plane processing device (11) holds in advance the cell information to be held in common with each of the user-plane processing devices (12.sub.1 to 12.sub.N) that are under control of the control-plane processing device. Each of the user-plane processing devices (12.sub.1 to 12.sub.N) requests the cell information from the control-plane processing device (11), for example, at a startup time. The control-plane processing device (11) notifies the cell information to be held in common with the relevant user-plane processing device to the user-plane processing device that has requested the cell information.