The present invention is designed to provide a radio base station apparatus which can acquire CSI reports at appropriate times, and which can trigger CSI reports effectively. The radio base station apparatus of the present invention has: a PDCCH signal generating section (211) that generates a downlink allocation signal for receiving and decoding downlink transmission data, the downlink allocation signal including a report request bit for triggering reporting of channel information aperiodically; a transmission section that transmits a downlink signal including a downlink control channel where the downlink allocation signal is mapped; and a receiving section that receives an uplink signal which includes the reporting of channel information from a terminal triggered by the report request bit, via the uplink.