To provide an interface between semiconductor integrated circuits capable of sharing a bus between the semiconductor integrated circuits and transferring data while restraining increase in hardware and software to the minimum.

The transfer of data between semiconductor integrated circuits is performed by frequency division. For example, when four LSIs LSI1, LSI2, LSI3, and LSI4 are connected to one bus 20, the transfer in the same bus between a plurality of LSIs can be performed simultaneously by modulating to 300 [MHz] between LSI1 and LSI4, and to 600 [MHz] between LSI2 and LSI3.