To avoid the situation that only specific data in date corresponding to a plurality of data types occupies a temporary storing part.An interface control part 26 of a data processing processor 10 sets data type information according to a data type of data which is requested to read. A memory controller 46 of an auxiliary storage device 40 controls the auxiliary storage device 40 to determine the data type requested based on the data type information contained in a read command from the data processing processor 10 and select a temporary storing region corresponding to the data type.