A control unit receives a data request signal transmitted from a data
recording apparatus, and then transmits a control parameter, which
corresponds to the data request signal, out of control parameters used to
execute control of a vehicle to the data recording apparatus. In this
case, a transmission state of a transmitting section at a time of
shutdown is stored as a communication history. Therefore, when the
communication history is stored in a storing section, the transmission
state at the time of shutdown is restored in a starting process executed
after a power supply is turned ON, based on the read communication
history.