An evaporator comprises: a housing with a refrigerant inlet and a refrigerant outlet; heat transfer tubes that are contained in the housing, in which chilled water for heat exchange with refrigerant inside the housing flows; at least one distribution tray that is placed apart from the heat transfer tubes and has a plurality of holes for distributing refrigerant over the underlying heat transfer tubes; a vapor-liquid separator that is placed apart from the bottom of the distribution tray and separates an introduced refrigerant into a vapor refrigerant and a liquid refrigerant; and a pair of support frames that are fixed to either side of the width direction of the housing, wherein the vapor-liquid separator comprises: a chamber that has an inlet port communicating with the refrigerant inlet, a vapor refrigerant exit communicating with the refrigerant outlet, and a plurality of holes formed in the bottom to distribute the liquid refrigerant to the distribution tray; and a plurality of side arms that are formed on either side of the chamber and arranged in the length direction of the chamber and supported by the support frames. Through the present disclosure, it is possible to keep the vapor-liquid separator horizontal and stable and achieve stable heat exchange performance.