To provide a gas refrigerant separator eased in restriction on a mounting direction when assembling it in a refrigeration device, a gas refrigerant separator-cum-refrigerant flow divider applying a gas refrigerant separating mechanism in the gas refrigerant separator, an expansion valve, and the refrigeration device.

This gas refrigerant separator-cum-refrigerant flow divider DR includes an introduction chamber 10 having a circular cross-section, a speed increase chamber 20 having a circular cross-section, and a delivery chamber 30 having a circular cross-section, which are serially and coaxially disposed. The delivery chamber 30 introduces therein a refrigerant from a refrigerant introduction opening 14 along an inner wall surface of the chamber and swirls the refrigerant. The speed increase chamber 20 increases a speed of the swirl flow of the refrigerant flowing from the introduction chamber 10, and discharges the refrigerant from a communication opening 21 at its front end, to the delivery chamber 30. The delivery chamber 30 has a diameter greater than a diameter of the communication opening 21 at the front end of the speed increase chamber 20. Also, the gas refrigerant separator-cum-refrigerant flow divider DR includes a gas refrigerant extraction pipe Pg for extracting a gas refrigerant from the center of the swirling refrigerant flow, and a refrigerant delivery pipe Pd for delivering the refrigerant from which the gas refrigerant has been extracted.