ONBOARD NETWORK SYSTEM

An on-vehicle network system includes, for each of a plurality of zones (Z) defined in a vehicle (10), a zone control unit (31), a power distributor (21) connected to an on-board battery (20), and a plurality of electronic devices (D) supplied with power from the power distributor (21) via a common power supply line (PC). Each of individual relays (RL) is interposed between one of the electronic devices (D) and a body ground of the vehicle (10) to individually turn on and off connection between the one of electronic device (D) and the body ground based on a control signal from the zone control unit (31).