The objective of the invention is to appropriately control feedback control information in an uplink transmission even in a case of using a carrier aggregation in HetNet. A user terminal, which can use a carrier aggregation to communicate with a plurality of radio base stations the coverage areas of which overlap each other, comprises: a reception unit that receives a downstream shared channel signal by use of the respective component carriers of primary and secondary cells; a generation unit that generates a transmittal acknowledgement signal for the received downstream shared channel signal; and an allocation unit that allocates the transmittal acknowledgement signal to a predetermined upstream control channel resource. The allocation unit allocates, in accordance with the content of the transmittal acknowledgement signal and/or an upstream control channel format, the transmittal acknowledgement signal to one or both of the upstream control channel resources of the primary and secondary cells.