It is an object to control the traffic that flows in a radio link to ensure the stability of the network as well as to prevent the deterioration of the communication quality due to the transmission of packets exceeding the capacity, and to increase the communication capacity. A communication control system in a packet mobile communication transmits a downlink packet from a base station to a mobile station via a radio network. The base station includes a transmission determiner that determines whether or not to transmit the downlink packet to the radio network in accordance with the state of congestion of the radio network and the traffic type (DSCP) of the downlink packet.