A fin tube type heat exchanger, comprising: a plurality of heat transfer fins (2, 12), the heat transfer fins being lined up such that they are spaced apart in the plate thickness directions and being disposed in a gas current; and a plurality of heat transfer tubes, the heat transfer tubes being inserted into the plurality of heat transfer fins and being disposed in directions substantially orthogonal to a gas current flow direction; wherein, in each of the heat transfer fins, a plurality of cut and raised parts (4a-4f, 14a-14f) are formed by a cutting and raising fabrication process on both sides of each of the heat transfer tubes in the vertical directions; the plurality of cut and raised parts are inclined with respect to the gas current flow direction such that the gas current in the vicinity of each of the heat transfer tubes is guided to a rear side in the gas current flow direction of that heat transfer tube; and wherein the heights of each of the cut and raised parts with respect to the heat transfer fin surface increase gradually toward the downstream side in the gas current flow direction; characterized in that: the cut and raised parts are lined up from the upstream side to the downstream side in the gas current flow direction, for each of the cut and raised parts, the value calculated by dividing the average height of the front end height, which is the height of the gas current flow direction front end with respect to the heat transfer fin surface, and the rear end height, which is the height of the gas current flow direction rear end with respect to the heat transfer fin surface, by a fin pitch, which is the spacing between the heat transfer fins, is greater than 0.3 and less than 0.6; and an inclination angle, which is an angle formed between a ridge of each of the cut and raised parts (4a-4f, 14a-14f) and the heat transfer fin surface, is less than 30°, wherein the plurality of cut and raised parts (4a-4f, 14a-14f) are disposed such that their average heights sequentially increase to be greater in the cut and raised parts on the downstream side in the gas current flow direction than in the cut and raised parts on the upstream side in the gas current flow direction, and the heat transfer fins (2, 12) are waffle shaped heat transfer fins. a plurality of heat transfer tubes, the heat transfer tubes being inserted into the plurality of heat transfer fins and being disposed in directions substantially orthogonal to a gas current flow direction; wherein, in each of the heat transfer fins, a plurality of cut and raised parts (4a-4f, 14a-14f) are formed by a cutting and raising fabrication process on both sides of each of the heat transfer tubes in the vertical directions; the plurality of cut and raised parts are inclined with respect to the gas current flow direction such that the gas current in the vicinity of each of the heat transfer tubes is guided to a rear side in the gas current flow direction of that heat transfer tube; and wherein the heights of each of the cut and raised parts with respect to the heat transfer fin surface increase gradually toward the downstream side in the gas current flow direction; characterized in that: the cut and raised parts are lined up from the upstream side to the downstream side in the gas current flow direction, for each of the cut and raised parts, the value calculated by dividing the average height of the front end height, which is the height of the gas current flow direction front end with respect to the heat transfer fin surface, and the rear end height, which is the height of the gas current flow direction rear end with respect to the heat transfer fin surface, by a fin pitch, which is the spacing between the heat transfer fins, is greater than 0.3 and less than 0.6; and an inclination angle, which is an angle formed between a ridge of each of the cut and raised parts (4a-4f, 14a-14f) and the heat transfer fin surface, is less than 30°, wherein the plurality of cut and raised parts (4a-4f, 14a-14f) are disposed such that their average heights sequentially increase to be greater in the cut and raised parts on the downstream side in the gas current flow direction than in the cut and raised parts on the upstream side in the gas current flow direction, and the heat transfer fins (2, 12) are waffle shaped heat transfer fins. the cut and raised parts are lined up from the upstream side to the downstream side in the gas current flow direction, for each of the cut and raised parts, the value calculated by dividing the average height of the front end height, which is the height of the gas current flow direction front end with respect to the heat transfer fin surface, and the rear end height, which is the height of the gas current flow direction rear end with respect to the heat transfer fin surface, by a fin pitch, which is the spacing between the heat transfer fins, is greater than 0.3 and less than 0.6; and an inclination angle, which is an angle formed between a ridge of each of the cut and raised parts (4a-4f, 14a-14f) and the heat transfer fin surface, is less than 30°, wherein the plurality of cut and raised parts (4a-4f, 14a-14f) are disposed such that their average heights sequentially increase to be greater in the cut and raised parts on the downstream side in the gas current flow direction than in the cut and raised parts on the upstream side in the gas current flow direction, and the heat transfer fins (2, 12) are waffle shaped heat transfer fins.