An object of the present invention is to avoid congestion, by restricting only processing which causes the congestion without affecting processing which essentially should not be restricted. In a mobile communication system according to the present invention, an exchange MSC/SGSN includes: a congestion factor detector configured to detect a congestion occurrence factor in the switching exchange MSC/SGSN, and a restriction indication transmitter configured to transmit, a restriction indication, to a radio network controller, based on the detected congestion occurrence factor, the restriction indication instructing a processing type that should be restricted in the switching exchange MSC/SGSN congestion occurrence factor. The radio network controller RNC is provided with a broadcast information transmitter configured to transmit broadcast information including the received restriction indication to a mobile station UE.