PURPOSE: To improve safety by the early execution of inspection while reducing the uncomfortable feelings of occupants caused by noise generated during inspecting operation.

CONSTITUTION: When door lock release operation is detected (S8) at the time of a driver getting on a vehicle next after getting off upon the end of driving, an initial check start command is outputted (S9), and the inspecting operation of a slip control device is performed according to the command. The inspecting operation is therefore performed before the driver getting on the vehicle, so that the uncomfortable feeling of occupants including the driver can be reduced. Since abnormality detection can be performed before starting to drive, the driver informed of the detected result can drive taking account of the detected result. Safety can be thereby improved.