A gas-liquid separator for separating a liquid and a gas from gas-liquid two-phase fluid by centrifugal force, the gas-liquid separator comprising: a swirling flow generating ribbon (30, 50) for swirling the gas-liquid two-phase fluid, the swirling flow generating ribbon (30, 50) formed from a helically twisted plate member; an inlet pipe (21, 41) that receives the swirling flow generating ribbon (30, 50) and comprises an inner surface to which a separated liquid is guided, the inlet pipe (21, 41) comprising, at a location downstream of a flow direction of the gas-liquid two-phase fluid from the swirling flow generating ribbon (30, 50), an exhaust port through which the gas flows out and a drain port through which the liquid flows out; and an inner pipe (22, 42) that is inserted into the exhaust port at an end, the inner pipe (22, 42) comprising an outer diameter smaller than an inner diameter of the inlet pipe (21, 41) and an opening that is open at a location downstream of the flow direction of the gas-liquid two-phase fluid from the swirling flow generating ribbon (30, 50), characterised in that, the swirling flow generating ribbon (30, 50) comprises, in a terminal end at a side where the gas-liquid two-phase fluid flows out, a first terminal end point that is in a first end of radially outward ends of the swirling flow generating ribbon (30, 50); a second terminal end point that is in a second end of radially outward ends of the swirling flow generating ribbon (30, 50); a middle terminal end point that is on an axial line of the swirling flow generating ribbon (30, 50) and at a location closer to a side where the gas-liquid two-phase fluid flows in the swirling flow generating ribbon (30, 50) than the first terminal end point and the second terminal end point; a terminal line between the first terminal end point and the second terminal end point is perpendicular to the axial line of the swirling flow generating ribbon; a first terminal edge connecting the first terminal end point and the middle terminal end point; a second terminal edge connecting the second terminal end point and the middle terminal end point, and in the terminal end of the swirling flow generating ribbon, a V shaped space or area is defined by the first terminal edge, the second terminal edge, and the terminal line, wherein the swirling flow generating ribbon (30, 50) comprises a folding back structure in the first terminal edge and the second terminal edge, the folding back structure being folded back toward the side where the gas-liquid two-phase fluid flows in the swirling flow generating ribbon (30, 50). a swirling flow generating ribbon (30, 50) for swirling the gas-liquid two-phase fluid, the swirling flow generating ribbon (30, 50) formed from a helically twisted plate member; an inlet pipe (21, 41) that receives the swirling flow generating ribbon (30, 50) and comprises an inner surface to which a separated liquid is guided, the inlet pipe (21, 41) comprising, at a location downstream of a flow direction of the gas-liquid two-phase fluid from the swirling flow generating ribbon (30, 50), an exhaust port through which the gas flows out and a drain port through which the liquid flows out; and an inner pipe (22, 42) that is inserted into the exhaust port at an end, the inner pipe (22, 42) comprising an outer diameter smaller than an inner diameter of the inlet pipe (21, 41) and an opening that is open at a location downstream of the flow direction of the gas-liquid two-phase fluid from the swirling flow generating ribbon (30, 50), characterised in that, the swirling flow generating ribbon (30, 50) comprises, in a terminal end at a side where the gas-liquid two-phase fluid flows out, a first terminal end point that is in a first end of radially outward ends of the swirling flow generating ribbon (30, 50); a second terminal end point that is in a second end of radially outward ends of the swirling flow generating ribbon (30, 50); a middle terminal end point that is on an axial line of the swirling flow generating ribbon (30, 50) and at a location closer to a side where the gas-liquid two-phase fluid flows in the swirling flow generating ribbon (30, 50) than the first terminal end point and the second terminal end point; a terminal line between the first terminal end point and the second terminal end point is perpendicular to the axial line of the swirling flow generating ribbon; a first terminal edge connecting the first terminal end point and the middle terminal end point; a second terminal edge connecting the second terminal end point and the middle terminal end point, and in the terminal end of the swirling flow generating ribbon, a V shaped space or area is defined by the first terminal edge, the second terminal edge, and the terminal line, wherein the swirling flow generating ribbon (30, 50) comprises a folding back structure in the first terminal edge and the second terminal edge, the folding back structure being folded back toward the side where the gas-liquid two-phase fluid flows in the swirling flow generating ribbon (30, 50).