An air conditioner comprising: a compressor; a first heat exchanger; a first pipe configured to allow refrigerant to flow from the first heat exchanger; a bypass pipe branched off from the first pipe and on which an expansion valve is provided; a second heat exchanger configured to allow the expanded refrigerant by the expansion valve to heat-exchange with the refrigerant flowing along the first pipe; a second pipe that couples the second heat exchanger to the compressor so that the refrigerant expanded by the expansion valve and heat-exchanged at the second heat exchanger can be introduced into the compressor; characterized in that it further comprises: an adjusting valve provided on the second pipe and opened when a degree of discharge superheat of the expanded refrigerant introduced to the compressor is above a first predetermined value; a first temperature sensor measuring a temperature of the expanded refrigerant introduced to the compressor through the second pipe; and a second temperature sensor measuring a temperature of the refrigerant expanded by the expansion valve and flowing into the second heat exchanger through the bypass pipe, wherein an opening of the expansion valve is adjusted such that a difference value between the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor reaches a second predetermined value. a compressor; a first heat exchanger; a first pipe configured to allow refrigerant to flow from the first heat exchanger; a bypass pipe branched off from the first pipe and on which an expansion valve is provided; a second heat exchanger configured to allow the expanded refrigerant by the expansion valve to heat-exchange with the refrigerant flowing along the first pipe; a second pipe that couples the second heat exchanger to the compressor so that the refrigerant expanded by the expansion valve and heat-exchanged at the second heat exchanger can be introduced into the compressor; characterized in that it further comprises: an adjusting valve provided on the second pipe and opened when a degree of discharge superheat of the expanded refrigerant introduced to the compressor is above a first predetermined value; a first temperature sensor measuring a temperature of the expanded refrigerant introduced to the compressor through the second pipe; and a second temperature sensor measuring a temperature of the refrigerant expanded by the expansion valve and flowing into the second heat exchanger through the bypass pipe, wherein an opening of the expansion valve is adjusted such that a difference value between the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor reaches a second predetermined value. an adjusting valve provided on the second pipe and opened when a degree of discharge superheat of the expanded refrigerant introduced to the compressor is above a first predetermined value; a first temperature sensor measuring a temperature of the expanded refrigerant introduced to the compressor through the second pipe; and a second temperature sensor measuring a temperature of the refrigerant expanded by the expansion valve and flowing into the second heat exchanger through the bypass pipe,