Abstract: A portion of an air-conditioning unit is divided into two so as to provide first and second air-mixing chambers each following first and second temperature adjustment mechanisms. The temperature of air in the first chamber is controlled independently of the temperature of air in the second chamber, while the first chamber communicates with a first group of air-conditioning zone or zones and the second chamber communicates with a second group of remaining zone or zones. Thus, the temperature of air fed to the first group can be controlled in a manner different from the temperature of air fed to the second group. A plurality of distributing valves are provided at air discharging outlets communicating with the first or second chambers, and the opening degree of each damper may be controlled so that air distribution amount may be controlled.