A built-in type compressor/condenser unit for an air conditioner is provided which prevents re-suction of discharged air. The built-in type compressor/condenser unit includes a louver frame which is installed on an inner portion of an outer wall of a building, and which divided into a suction area and a discharge area each having a plurality of louver blades. A compressor/condenser casing is installed in contact with the louver frame, having its surface facing the suction area and the discharge area of the louver frame opened and the other surfaces closed. The compressor/condenser unit is divided into a suction unit and a discharge unit corresponding to the suction area and the discharge area of the louver frame. The louver frame includes an isolating means for isolating air between the suction area and the discharge area so as to prevent air discharged from the discharge unit thought the discharge area from being re-ingested into the suction unit through the suction area of the louver frame.