In an evaporator unit for a refrigerant cycle device, an evaporator is connected to an ejector to evaporate refrigerant to be drawn into a refrigerant suction port of the ejector or the refrigerant flowing out of the outlet of the ejector. The evaporator includes a plurality of tubes in which the refrigerant flows, and a tank configured to distribute the refrigerant into the tubes or to collect the refrigerant from the tubes. The ejector is located in the tank, and the nozzle portion is brazed to the tank to be fixed into the tank. The tank may be a header tank directly connected to the tubes or may be a separate tank separated from the header tank.