ONBOARD NETWORK SYSTEM

An on-vehicle network system includes, for each of a plurality of zones defined in a vehicle, a zone control unit, a power distributor connected to an on-board battery, and a plurality of electronic devices supplied with power from the power distributor via a common power supply line. Each of individual relays is interposed between one of the electronic devices and a body ground of the vehicle to individually turn on and off connection between the one of electronic device and the body ground based on a control signal from the zone control unit.