AIR CONDTIONER

An air conditioner of the present invention includes: an outdoor unit including a compressor, a heat changeover valve, an outdoor heat exchanger, and an outdoor expansion device connected by a coolant flow path; an indoor unit including an indoor expansion device and an indoor heat exchanger connected by a coolant flow path; a gas pipe connecting the indoor heat exchanger and the heat changeover valve; a fluid pipe connecting the outdoor expansion device and the indoor expansion device; and a heat source unit including a receiver connected to the fluid pipe by a first flow path, a water coolant heat exchanger which is connected to the receiver through a second flow path and to the area between the heat changeover valve and the outdoor heat exchanger by a third flow path to enable the heat exchange between the coolant and water from a heat source, and a heat source expansion unit installed on the second flow path. The heat source unit can be easily connected to the fluid pipe and the outdoor unit to install the heat source unit freely.