To prevent deformation of a gas-liquid separating member due to pressure of a refrigerant flowing into a gas-liquid separator.

In a gas-liquid separator 1 including a cylindrical body 2 opened at one end, a header 3 sealing an opening end of the body 2, and provided with a refrigerant inflow hole 3d and a refrigerant outflow hole 3e, and a gas-liquid separating member 7 disposed on a position opposed to an inner face of the header 3, and separating the refrigerant flowing therein from the refrigerant inflow hole 3d of the header 3 into a gas and a liquid, separating the refrigerant flowing in from the refrigerant inflow hole 3d of the header 3 into a gas and a liquid, and guiding the separated gas refrigerant to the refrigerant outflow hole 3e with an oil accumulated on a bottom section of the body 2, the gas-liquid separating member 7 has ribs 7b on a face opposed to the header 3, the header 3 has groove sections 3h corresponding to the ribs 7b, on a face opposed to the gas-liquid separating member 7, and the groove section 3h and the rib 7b are fitted to each other.