Air conditioner

An air conditioner for supplying air-conditioned air to a room through an air supply duct by operating an air blower, the air conditioner having a housing, the shell is provided with an external air port for taking in external air, an air supply port connected with an air supply pipeline and used for supplying the external air taken in from the external air port to a room, an air return port for taking in air from the room, and an exhaust port for exhausting the air taken in from the air return port to the outside. Furthermore, the air conditioner is provided with: an outside air-side air passage which is formed inside the housing and which connects the outside air port and the air supply port; an exhaust-side air passage formed inside the housing so as to be separated from the outside-air-side air passage, the exhaust-side air passage communicating the return air port and the exhaust port; an indoor heat exchanger which is disposed in the outside air-side air path and through which a refrigerant flows; an ai