An air conditioner, comprising: a compressor for compressing a refrigerant, the compressor having a high pressure side and a low pressure side; a condenser for condensing the refrigerant compressed at the compressor; an evaporator for evaporating the refrigerant condensed at the condenser; and an injection module configured to selectively or simultaneously inject a portion of the refrigerant flowing from the condenser to the evaporator into the high pressure side and the low pressure side of the compressor, wherein the injection module comprises: an injection expansion valve for expanding the portion of the refrigerant; an injection heat exchanger for heat-exchanging and evaporating the portion of the refrigerant expanded at the injection expansion valve with the refrigerant flowing from the condenser; a high pressure injection valve, disposed between the injection heat exchanger and the high pressure side of the compressor, configured to control the flow of the refrigerant evaporated by the injection heat exchanger; and a low pressure injection valve, disposed between the injection heat exchanger and the low pressure side of the compressor, configured to control the flow of the refrigerant evaporated by the injection heat exchanger, wherein the injection heat exchanger is connected to the condenser, the injection expansion valve, the high pressure injection valve, and the low pressure injection valve. a compressor for compressing a refrigerant, the compressor having a high pressure side and a low pressure side; a condenser for condensing the refrigerant compressed at the compressor; an evaporator for evaporating the refrigerant condensed at the condenser; and an injection module configured to selectively or simultaneously inject a portion of the refrigerant flowing from the condenser to the evaporator into the high pressure side and the low pressure side of the compressor, wherein the injection module comprises: an injection expansion valve for expanding the portion of the refrigerant; an injection heat exchanger for heat-exchanging and evaporating the portion of the refrigerant expanded at the injection expansion valve with the refrigerant flowing from the condenser; a high pressure injection valve, disposed between the injection heat exchanger and the high pressure side of the compressor, configured to control the flow of the refrigerant evaporated by the injection heat exchanger; and a low pressure injection valve, disposed between the injection heat exchanger and the low pressure side of the compressor, configured to control the flow of the refrigerant evaporated by the injection heat exchanger, wherein the injection heat exchanger is connected to the condenser, the injection expansion valve, the high pressure injection valve, and the low pressure injection valve. an injection expansion valve for expanding the portion of the refrigerant; an injection heat exchanger for heat-exchanging and evaporating the portion of the refrigerant expanded at the injection expansion valve with the refrigerant flowing from the condenser; a high pressure injection valve, disposed between the injection heat exchanger and the high pressure side of the compressor, configured to control the flow of the refrigerant evaporated by the injection heat exchanger; and a low pressure injection valve, disposed between the injection heat exchanger and the low pressure side of the compressor, configured to control the flow of the refrigerant evaporated by the injection heat exchanger, wherein the injection heat exchanger is connected to the condenser, the injection expansion valve, the high pressure injection valve, and the low pressure injection valve.