A gas-liquid separation device for a vehicle according to an embodiment of the present disclosure includes: a housing with an upper surface that is opened and a lower surface that is closed; a cover mounted on the opened upper surface to close and seal the interior of the housing, and including an outlet and an inlet, and a mount hole; an exhaust pipe mounted on the cover; a guide pipe with an upper surface that is opened so that the exhaust pipe is inserted inside, and forms a gas refrigerant flow space between the exterior circumference and the interior circumference of the exhaust pipe; a mount cap mounted inside the closed lower end of the housing; a refrigerant guider to prevent the liquid refrigerant of the refrigerant inflowed into the inlet from flowing into the gas refrigerant flow space, and fixed to the exhaust pipe; and a receiver dryer.