A method for setting an apparatus using refrigerant, the method comprising: sealing an incombustible refrigerant in a refrigerant circuit component part of an outdoor unit, shipping the outdoor unit from a factory, and setting the outdoor unit; connecting the refrigerant circuit component part of the set outdoor unit to a load-side apparatus of an indoor unit by connecting the liquid extension pipe to a liquid pipe connection valve of the outdoor unit and a liquid pipe connecting port of the indoor unit, wherein the liquid pipe connection valve comprises a switching valve in a fully closed state, and by connecting the gas extension pipe to a gas pipe connection valve of the outdoor unit and a gas pipe connecting port of the indoor unit, wherein the gas pipe connection valve comprises a first switching valve and a second switching valve in a fully closed state, thereby forming a refrigerant circuit,; connecting a vacuum pump to the load-side apparatus to which the extension pipes (10, 11) are connected by connecting the vacuum pump to a connecting port of the gas pipe connection valve, opening the second switching valve of the gas pipe connection valve, evacuating the load-side apparatus and the extension pipes (10, 11); closing the second switching valve of the gas pipe connection valve and disconnecting the vacuum pump, connecting a container containing combustible refrigerant or slightly combustible refrigerant to the load-side apparatus by connecting the container to the connecting port of the gas pipe connection valve, and sealing the combustible refrigerant or the slightly combustible refrigerant in the load-side apparatus and the extension pipes (10, 11) by opening the second switching valve of the gas pipe connection valve,; and after sealing of the combustible refrigerant or the slightly combustible refrigerant in the load-side apparatus and the extension pipes, closing the second switching valve of the gas pipe connection valve, and bringing the load-side apparatus, the extension pipes (10, 11), and the refrigerant circuit component part of the outdoor unit in mutual communication by opening the first switching valve of the gas pipe connection valve and the switching valve of the liquid pipe connection valve, so that the refrigerant can circulate through the load-side apparatus, the extension pipes (10, 11), and the refrigerant circuit component part. sealing an incombustible refrigerant in a refrigerant circuit component part of an outdoor unit, shipping the outdoor unit from a factory, and setting the outdoor unit; connecting the refrigerant circuit component part of the set outdoor unit to a load-side apparatus of an indoor unit by connecting the liquid extension pipe to a liquid pipe connection valve of the outdoor unit and a liquid pipe connecting port of the indoor unit, wherein the liquid pipe connection valve comprises a switching valve in a fully closed state, and by connecting the gas extension pipe to a gas pipe connection valve of the outdoor unit and a gas pipe connecting port of the indoor unit, wherein the gas pipe connection valve comprises a first switching valve and a second switching valve in a fully closed state, thereby forming a refrigerant circuit,; connecting a vacuum pump to the load-side apparatus to which the extension pipes (10, 11) are connected by connecting the vacuum pump to a connecting port of the gas pipe connection valve, opening the second switching valve of the gas pipe connection valve, evacuating the load-side apparatus and the extension pipes (10, 11); closing the second switching valve of the gas pipe connection valve and disconnecting the vacuum pump, connecting a container containing combustible refrigerant or slightly combustible refrigerant to the load-side apparatus by connecting the container to the connecting port of the gas pipe connection valve, and sealing the combustible refrigerant or the slightly combustible refrigerant in the load-side apparatus and the extension pipes (10, 11) by opening the second switching valve of the gas pipe connection valve,; and after sealing of the combustible refrigerant or the slightly combustible refrigerant in the load-side apparatus and the extension pipes, closing the second switching valve of the gas pipe connection valve, and bringing the load-side apparatus, the extension pipes (10, 11), and the refrigerant circuit component part of the outdoor unit in mutual communication by opening the first switching valve of the gas pipe connection valve and the switching valve of the liquid pipe connection valve, so that the refrigerant can circulate through the load-side apparatus, the extension pipes (10, 11), and the refrigerant circuit component part.