Abstract: A fin-and-tube heat exchanger comprises a fin plate, a heat exchanger tube having portions extending through the fin plate, a plurality of fin collars formed in the plate, wherein louvers are provided so as to surround the tube portions except areas nearest to the collars, the louvers are in parallel with one another and project from alternately both surfaces of the plate, the louver which is located at the trailing edge side and at a position near to a central line of the tube bank is longitudinally extended so as to be along the collars and has opposite rising ends extending from the plate slanted toward the corresponding tube portions at an angle of 35 deg or below to the flow direction of the fluid, and the louver which is located at a position nearer to the trailing edge is also longitudinally extended and has opposite rising ends extending from the plate slanted toward the corresponding tube portions at an angle of 35 deg or above to the flow direction of the fluid so that the angle between the rising e