other in such a manner that the height h 2 of the dimple 102 placed in the rear section of the fin body 103 in the direction of air flow is higher than the height h 1 of the dimple 102 placed in the front section of the fin body 102 as shown in fig1 b the surface areas of the rear dimples 102 are thus increased with such a difference of surface area between the front dimples 102 and the rear dimples 102 the heat exchanger compensates for the heat transfer rate of the air passing by the rear dimples 102 which heat transfer rate is relatively lower than that of the air passing by the front dimples 102 hence the heat transfer rate between the air introduced into the heat exchanger 70 and the exterior surfaces of the fin bodies 103 is improved fig1 a to 13c are side views showing different air currents about fin bodies 103 in accordance with positions of dimples 102 formed on the fin bodies 103 of the heat exchanger of fig1 respectively as described above the present invention provides a fin tube type heat exchanger which improves heat transfer rate between a fin body and the air by forming dimples instead of typical louvered fins on the exterior surface of the fin body provision of the dimples instead of the louvered fins also facilitate production of the fin tube type heat exchanger in the fin tube type heat exchanger of the invention the heat transfer rate between.