PURPOSE: To prevent indoor air or surrounding atmosphere from entered or exited along a floor surface of the entrance or exit by a method an air conditioning air blowing port is arranged at an upper part of an indoor portion in parallel with its flowing direction and an air guiding vertical member for guiding the air conditioning air to a floor surface is arranged in the flowing direction.

CONSTITUTION: Air conditioning air blown from air conditioning air blowing ports 202 and 202 is flowed down along air guiding vertical members 142 and 142 acting as air guiding vertical members 132 and 132 or an opening door under Coanda effect, reaches a floor surface 23. It flows along the floor 23 and across a flowing direction against entrance or exit ports 101 and 102 and then accumulated in sequence on the floor 23. Either indoor air under a cooling action or surrounding air under a heating action is prevented from being flowed along the floor 23 and passed through the entrance port 101 and 102. In addition, both temperature and air speed of indoor air or surrounding air passing through the entrance port 101 and 102 are measured by a temperature sensor 40 and an air speed sensor 50, a temperature of air and air speed of air blown from the air conditioning air blowing ports 202 and 202 are adjusted and a downward-directed flow is adjusted by a louver so as to perform a more efficient air conditioning operation.