A circuit body for a vehicle is wired on a vehicle body of the vehicle for performing supply of electric power to an electrical component and communication of various communication signals with the electrical component. The circuit body includes: a plurality of control boxes separately disposed on the circuit body and capable of controlling input and output of at least one of the electric power and the communication signal; a trunk line harness connecting one of the plurality of control boxes and another of the plurality of control boxes; and a branch line harness connecting the control box and the electrical component. At least one of the plurality of control boxes is grounded via the electrical component connected to the branch line harness.