A radio base station according to this invention includes: a radio resource allocation determination unit for determining whether or not to allocate a radio resource to a mobile communication device; a radio resource control unit for allocating the radio resource to the mobile communication device to which the radio resource allocation determination unit has determined to carry out the allocation of the radio resource; and a backhaul line control unit for providing control of outputting data received from the mobile communication device to a backhaul line for relaying the data to a higher-level network. When congestion occurs, the radio resource control unit reduces an amount of the radio resource to be allocated, and the radio resource allocation determination unit determines whether or not to allocate the radio resource to another mobile communication device, depending on whether or not the received data satisfies predetermined service quality.