To efficiently transfer data.

In accordance with a control command from a bus master 10, transfer data are transmitted/received through a bus 10 to/from an application 20 instructed by the control command. The setting of data width is made variable, and the same or several kinds of data are included in a single packet so that the same or several kinds of data can be simultaneously outputted to the bus. Thus, the bus width can be effectively used, and the data can be efficiently transferred. For example, when the width of each transfer data is smaller than the bus width, a plurality of data can be simultaneously outputted to the bus. Thus, more efficient data transfer can be performed than a PCI.