To solve discomfort to sit, which is generated by the discontinuity of seat back configuration when operating a lumbar support device in a vehicle in which the lumbar support device and a heating/cooling ventilated seat with a thermoelectric device form are simultaneously applied.

The present invention provides an apparatus for mounting a thermoelectric device in a heating/cooling ventilated seat incorporating a lumbar support device. The thermoelectric device is mounted to a seat back load support structure which is affixed to a rear portion of the seat back cushion by a mounting bracket such that the entire upper and lower end portion of the seat back cushion can move forward and backward when the lumbar support device in operated.