To eliminate fear for accumulating ozone in a living room, and to eliminate fear of corroding a heat exchange fan coil by ozone by providing an ozone decomposing filter in an intake port of an air conditioning fan coil unit of the living room, and providing an ozone mixer in a blowoff port.

Air in a living room is introduced to an ozone decomposing filter 2 from an intake port 1 of a fan coil unit to decompose a trace quantity of ozone contained in the air. This air is blown in a heat exchange fan coil 4 by an air blower 3, and is blown off in the living room after mixing the ozone by an ozone mixer 5 arranged in a blowoff port. A cassette by filling honeycomb-shaped activated charcoal or granular activated charcoal in a shallow bottom tray having the bottom of a wire net is used as the ozone decomposing filter 2, and a ceramic or Teflon cylindrical porous filter is used as the ozone mixer 5. When using this filter, the air and the ozone are excellently mixed to uniformize the ozone concentration in the air blowing off from the fan coil unit.