The present invention is to provide a bus arbitration apparatus and a bus arbitration method not reducing data transfer capability as a whole and preventing a loss of transferred data. It performs the arbitration with priority in response to properties of bus masters. It sequentially arbitrates a first hierarchy bus master of which requests are urgent, a second hierarchy bus master that requests data processing in real time, and a third hierarchy bus master that is neither a first hierarchy bus master nor a second hierarchy bus master sequentially.