PURPOSE: To separate a seat part from a leg part and to easily perform assembling at a site by separately forming a driving part for reclining for a seat back on the seat part and a driving part for elevation on the leg part, respectively.

CONSTITUTION: The leg part B equipped with an elevation driving device to elevate a seat and the seat part A equipped with a reclining driving device to recline the seat back are coupled by unifying so as to be separated by a coupling means. In this way, since the seat part A can be separated from the leg part B when they are shipped from a factory, bulk can be reduced, and also, they can be easily assembled at the site, which enables transportation and stock to be easily performed.