In a memory controller, command, address and data are allocated to transmit the command, the address and the data to each of the plurality of memory devices through the same bus signal line and an identification signal to identify the command, the address and the data on the bus signal line is allocated to a memory common signal line in common among the plurality of memory devices to transmit the identification signal. When the memory controller indicates the data through the identification signal so as to make a first memory device transfer the data through the bus signal line, the memory controller makes the data transfer by the first memory device suspended, indicates the command through the identification signal so as to issue the command to a second memory device, and indicates the address through the identification signal so as to issue the address to the second memory device.