In a radio communication apparatus, a MIMO system deciding section of a transmitter unit decides an object MIMO communication system with reference to a CQI value and a measured rate table while an AMC table controlling section selects an object MCS value according to the decided MIMO communication system and CQI value. The AMC table controlling section changes the MCS value step by step according to a transmission count and a result (success/failure) of the communication. If the communication (receiving) is successful or if the transmission count reaches the maximum value, the controlling section updates the mean value of the measured rate table. At this time, based on a value estimated from the combination of the MIMO communication system, the encoding system, and the modulating system that are used currently, the controlling section changes the reference for selecting another combination that are not used currently.