To execute air conditioning by a head cooling/foot heating comfortable system within a room by arranging a plurality of room heat exchangers on a wall of a building with a clearance made from the top to bottom thereof.

As a room heat exchanger 7 acts as condenser, relatively high temperature air is blown out to a part near a floor surface in a room by sending the air from a fan 7a. Then, as a refrigerant with the temperature thereof dropping slightly is introduced to a room heat exchanger 6 passing through a refrigerant piping 16 in a wall W, the room heat exchanger 6 acts as condenser and hot air with the temperature thereof slightly lower than that at a lower part in the room is blown to a part near the ceiling in the room by sending the air from the fan 6a. Thus, relatively high temperature hot air is blown out from a lower room unit 2 and the hot air with the temperature thereof lower that it is blown out from an upper room unit 1 thereby realizing a room heating of a so-called head cooling/foot heating type.