A wire harness includes a power source line and a signal line which connect a control ECU for controlling motor units disposed on each seat of a vehicle, switch units for operating the motor units and the motor units to each other. Drive connectors in which drive circuits for driving the motor units are incorporated are provided to terminals of the wire harness on a motor units side. Signal connectors for transmitting operation signals indicative of states of the switch units are mounted on terminals of the wire harness on a switch units side. The drive connectors and the signal connectors are provided as parts separate from each other, and the control ECU, the drive connectors and the signal connectors are provided that multiplex communication is possible among them through the signal line.