An integrated vehicle control system includes various functionalized networks, such as power train group, vehicle motion group, and power source group, each including a plurality of ECUs connected via an individual communication line. A managing ECU in each network determines operation directives to be supplied to individual ECUs belonging to its own network based on information obtained from these individual ECUs as well as information obtained from other ECUs of different networks via a host communication line L4. The determined operation directives are transmitted to corresponding ECUs to cause respective individual ECUs to operate subordinately according to the given operation directives, thereby realizing a collective control of specific functions. The managing ECU also executes abnormality detection processing for detecting abnormality occurring in the integrated vehicle control system.