WIRING JUNCTION BOX

Provided is a wiring junction box for branching a wire connected to a plurality of ECUs mounted in a vehicle, including: a power input terminal connected to an electrical storage device supplying electric power to the ECUs; a plurality of power output terminals respectively outputing electric power input from the power input terminal to the plurality of ECUs; a communication device-side communication port connected to a communication device communicating with the ECUs; and a plurality of ECU-side communication ports respectively connected to the plurality of ECUs, wherein the wire includes a power line for connecting the power input terminal and the power output terminals and a communication line for connecting the communication device-side communication port and the ECU-side communication ports, the power line branches according to the number of power output terminals, and the communication line branches according to the number of ECU-side communication ports.