An air conditioning device, comprising: a plurality of indoor units (300A to 300E) that each performs heat exchange to heat or cool a corresponding space; an outdoor unit operably coupled to each of the indoor units, the outdoor unit including a compressor, an outdoor heat exchanger, and a blowing fan; a distribution unit assembly detachably installed in the outdoor unit and a liquid state refrigerant pipe and a gas state refrigerant pipe connecting the distribution unit assembly with the outdoor unit; wherein the distribution unit assembly comprises: a basic distribution unit module having an indoor unit connection part comprising indoor side high-pressure sockets (271A-1, 271A-2) and indoor side low-pressure-sockets (275A-1, 275A-2) connected to at least one indoor unit of the air conditioning device, an outdoor unit connection part connected to the liquid state refrigerant pipe and the gas state refrigerant pipe, and a distribution unit housing forming the external appearance of the basic distribution unit module, characterized in that the distribution unit assembly additionally comprises: at least one additional distribution unit module having an indoor unit connection part comprising indoor side high-pressure sockets (271B-1, 271B-2) and indoor side low-pressure-sockets (275B-1, 275B-2) connected to at least one indoor unit of the air conditioning device, a distribution unit connection part connected to the basic distribution unit module, and an additional distribution unit housing forming the external appearance of the additional distribution unit module, wherein the basic distribution unit module and the additional distribution unit module are coupled to each other in a stacked structure to constitute the distribution unit assembly. a plurality of indoor units (300A to 300E) that each performs heat exchange to heat or cool a corresponding space; an outdoor unit operably coupled to each of the indoor units, the outdoor unit including a compressor, an outdoor heat exchanger, and a blowing fan; a distribution unit assembly detachably installed in the outdoor unit and a liquid state refrigerant pipe and a gas state refrigerant pipe connecting the distribution unit assembly with the outdoor unit; wherein the distribution unit assembly comprises: a basic distribution unit module having an indoor unit connection part comprising indoor side high-pressure sockets (271A-1, 271A-2) and indoor side low-pressure-sockets (275A-1, 275A-2) connected to at least one indoor unit of the air conditioning device, an outdoor unit connection part connected to the liquid state refrigerant pipe and the gas state refrigerant pipe, and a distribution unit housing forming the external appearance of the basic distribution unit module, characterized in that the distribution unit assembly additionally comprises: at least one additional distribution unit module having an indoor unit connection part comprising indoor side high-pressure sockets (271B-1, 271B-2) and indoor side low-pressure-sockets (275B-1, 275B-2) connected to at least one indoor unit of the air conditioning device, a distribution unit connection part connected to the basic distribution unit module, and an additional distribution unit housing forming the external appearance of the additional distribution unit module, wherein the basic distribution unit module and the additional distribution unit module are coupled to each other in a stacked structure to constitute the distribution unit assembly. a basic distribution unit module having an indoor unit connection part comprising indoor side high-pressure sockets (271A-1, 271A-2) and indoor side low-pressure-sockets (275A-1, 275A-2) connected to at least one indoor unit of the air conditioning device, an outdoor unit connection part connected to the liquid state refrigerant pipe and the gas state refrigerant pipe, and a distribution unit housing forming the external appearance of the basic distribution unit module, characterized in that the distribution unit assembly additionally comprises: at least one additional distribution unit module having an indoor unit connection part comprising indoor side high-pressure sockets (271B-1, 271B-2) and indoor side low-pressure-sockets (275B-1, 275B-2) connected to at least one indoor unit of the air conditioning device, a distribution unit connection part connected to the basic distribution unit module, and an additional distribution unit housing forming the external appearance of the additional distribution unit module, wherein the basic distribution unit module and the additional distribution unit module are coupled to each other in a stacked structure to constitute the distribution unit assembly. at least one additional distribution unit module having an indoor unit connection part comprising indoor side high-pressure sockets (271B-1, 271B-2) and indoor side low-pressure-sockets (275B-1, 275B-2) connected to at least one indoor unit of the air conditioning device, a distribution unit connection part connected to the basic distribution unit module, and an additional distribution unit housing forming the external appearance of the additional distribution unit module, wherein the basic distribution unit module and the additional distribution unit module are coupled to each other in a stacked structure to constitute the distribution unit assembly.