HEAT EXCHANGER

PURPOSE:To reduce a water holding amount in an evaporator or reduce an aeration resistance by a method wherein a remained amount of water droplet at a downstream end of each of plate fins or corrugated fins to which a water repellant treatment is applied at their surfaces. CONSTITUTION:An evaporator 1 in which surfaces of a plurality of plate fins 5 having a plurality of tubes 9 passed therethrough are treated with water repellant processing is constructed such that there is provided a net 10 of which surface is treated with hydrophilic processing under contacted or non-contacted state at downstream ends of the plate fins 5. Water droplets adhered to the surfaces of the plate fins 5 reach the downstream ends of the plate fins while entraining the water droplets at the downstream ends with air, resulting in that the water droplets are flowed down after they are caught in such a way that they are retracted toward the net 10. With such an arrangement as above, a remained amount of water droplets at the downstream ends of the plate fins 5 of which surfaces are treated in water repellant is reduced.