A vehicle customizing system is highly reliable in the event of communication failures. For setting control characteristic values pertaining to functions of control units to control characteristic values favored by the user, the functions and the present control characteristic values set for the functions are displayed on a display unit. The control characteristic values, which are changed using the display unit, are stored in first function information tables of the control units, which directly perform the functions. Even in the event of a communication failure, the control units are capable, on their own, of controlled objects in order to perform the functions thereof based on the control characteristic values stored in the first function information tables.