A vapor-liquid separator is disclosed which is capable of improving a dischargeability of a separated liquid and of suppressing a reversed flow. The present vapor-liquid separator comprises a cylindrical separator main body, an introducing part for introducing the vapor-liquid mixed fluid into the separator main body in the tangential direction, a liquid discharging part for discharging a separated liquid, a gas exhausting part for exhausting the separated gas, a storing part for storing a liquid passed through the liquid discharging part, a stored-liquid discharging part provided in the storing part to discharge a stored liquid and a communicating part for communicating the storing part with an upstream side of a vapor-liquid separation region of the separator main body and/or the introducing part.