A first evaporation unit and a second evaporation unit are coupled via a refrigerant interchanging portion having a first communication portion and a second communication portion. A first partition member is provided in a tank portion of the first evaporation unit to define a first tank internal space and a second tank internal space. The first partition member has a first communication hole to let the first tank internal space and the second tank internal space communicate with each other. A second partition member is provided in a tank portion of the second evaporation unit to define a third tank internal space and a fourth tank internal space. The second partition member has a second communication hole to let the third tank internal space and the fourth tank internal space communicate with each other.