A flat wiring body module includes a flat wiring body, a containing member containing the flat wiring body, and a connector part. The flat wiring body includes a flat wiring body for power including a power circuit and a first flat board, a flat wiring body for non-power including a non-power circuit and a second flat board, and a flat wiring body for ground including a ground and a third flat board. The flat wiring body for power, the flat wiring body for non-power, and the flat wiring body for ground are stacked in a state where the flat wiring body for ground is arranged between the flat wiring body for power and the flat wiring body for non-power.