The present invention is designed to effectively apply carrier aggregation and Coordinated Multiple Point (CoMP) transmission/reception in a system band that is formed with a plurality of fundamental frequency blocks. A radio communication system where carrier aggregation is applicable in the same frequency band, and, this radio communication system includes the first radio base station apparatus and a second radio base station apparatus that perform coordinated multiple point transmission to a user terminal using cells having the same frequency band, and the first radio base station apparatus and the second radio base station apparatus perform retransmission control for uplink signals from the user terminal on a shared basis, and perform mapping of downlink signals to radio resources separately.