A built-in type compressor/condenser unit for an air conditioner with an efficient installation structure for installing an increased capacity outdoor unit is provided. The built-in type compressor/condenser unit includes a louver frame installed on a rectangular shaped space formed on an outer wall of a building. The louver frame is divided into a suction area and a discharge area, each with a plurality of louver blades. The compressor/condenser unit casing is positioned proximate the louver frame, with the surface of the casing which faces the suction area and the discharge area of the louver frame open, and the remaining surfaces of the casing closed. A compressor, an air-cooled condenser, and a cooling fan are installed in the compressor/condenser unit casing.