1. A mobile station comprising:a processor that manages flow priorities assigned to data flows to be transmitted to a radio base station via radio bearers;
the processor performs priority control based on priorities assigned in relation to Flow Priority Indicators (FPIs) and Quality of Service Class Identifiers (QCIs), FPI indicating a flow priority of each data flow, and QCI indicating a class of Quality of Service,
the processor performs priority control over the data flows to be transmitted to the radio base station via the radio bearers,
the processor establishes a radio bearer with the radio base station for each of the flow priorities, and
the processor transfers each data flow to the radio bearer corresponding to the flow priority assigned to the data flow; and
a transmitter that transmits the data flow to the radio base station via the corresponding radio bearer,
wherein each of the flow priorities has a respective discard timer for discarding data in the corresponding data flow if a buffering time of the data exceeds a predetermined period.