A refrigeration cycle apparatus comprising: a main circuit through which refrigerant circulates and in which a compressor , a condenser, a first expansion device , a centrifugal gas-liquid separator that separates refrigerant into gas refrigerant and liquid refrigerant by using centrifugal force, and an evaporator are connected by refrigerant pipes ; and a bypass through which the gas refrigerant obtained through the separation by the gas-liquid separator is returned to a suction side of the compressor , wherein the gas-liquid separator includes a cylindrical container , an inflow pipe , a gas outflow pipe , and a liquid outflow pipe , wherein the main circuit includes a third expansion device provided between the liquid outflow pipe of the gas-liquid separator and the evaporator, wherein the gas refrigerant discharged from the gas outflow pipe of the gas-liquid separator flows into the bypass , and the bypass is provided with a second expansion device , characterised in that , in the gas-liquid separator , the inflow pipe is inserted through an upper part of a side wall of the container , and the gas outflow pipe extends vertically through a central part of an upper wall of the container , wherein 0.26H 1 ≤ L 1 ≤ 0.65H 1 is satisfied where H 1 is a height of the container and L 1 is a gas-outflow-pipe insertion length representing a length of insertion of the gas outflow pipe from an upper end of the container , and wherein 0.25H 1 < L 1 -H 2 is satisfied where H 2 is a vertical distance from the upper end of container to a height-direction position of insertion of the inflow pipe and thus the L 1 -H 2 expresses a height-direction distance from the height-direction position of insertion of the inflow pipe to a gas outlet of the gas outflow pipe . a main circuit through which refrigerant circulates and in which a compressor , a condenser, a first expansion device , a centrifugal gas-liquid separator that separates refrigerant into gas refrigerant and liquid refrigerant by using centrifugal force, and an evaporator are connected by refrigerant pipes ; and a bypass through which the gas refrigerant obtained through the separation by the gas-liquid separator is returned to a suction side of the compressor , wherein the gas-liquid separator includes a cylindrical container , an inflow pipe , a gas outflow pipe , and a liquid outflow pipe , wherein the main circuit includes a third expansion device provided between the liquid outflow pipe of the gas-liquid separator and the evaporator, wherein the gas refrigerant discharged from the gas outflow pipe of the gas-liquid separator flows into the bypass , and the bypass is provided with a second expansion device , characterised in that , in the gas-liquid separator , the inflow pipe is inserted through an upper part of a side wall of the container , and the gas outflow pipe extends vertically through a central part of an upper wall of the container , wherein 0.26H 1 ≤ L 1 ≤ 0.65H 1 is satisfied where H 1 is a height of the container and L 1 is a gas-outflow-pipe insertion length representing a length of insertion of the gas outflow pipe from an upper end of the container , and wherein 0.25H 1 < L 1 -H 2 is satisfied where H 2 is a vertical distance from the upper end of container to a height-direction position of insertion of the inflow pipe and thus the L 1 -H 2 expresses a height-direction distance from the height-direction position of insertion of the inflow pipe to a gas outlet of the gas outflow pipe . <EOS>