This vehicle circuit routing system as a whole has a backbone-like routing structure, said system being provided with a plurality of backbone JB structures, wherein the vehicle circuit bodies of the backbone JB structures are connected to each other by means of a backbone main line. Each vehicle circuit body is provided with a power supply circuit that is connected to a main power supply on the vehicle, a plurality of connection parts to which a plurality of branch lines having a power supply line are connected, and a control unit that controls the distribution of power from the power supply circuit to the branch lines.