A heat exchanger, comprising a plurality of heat exchange members arranged side by side in a first direction so as to be spaced apart from each other, wherein each of the plurality of heat exchange members includes: a main body portion including a heat transfer pipe extending in a second direction intersecting with the first direction; and extending portions provided to the main body portion along the second direction, wherein the extending portions extend from ends of the main body portion in a third direction intersecting with both of the first direction and the second direction, and wherein, when a dimension of the main body portion in the third direction is represented by La [mm], a dimension of the extending portions in the third direction is represented by Lf [mm], a dimension of a wall thickness of each of the heat transfer pipes is represented by tp [mm], and a thickness dimension of each of the extending portions is represented by Tf [mm], relationship: Tf ≤ tp is satisfied; and wherein, when a dimension of each of the main body portions in a direction orthogonal to both of the second direction and the third direction is represented by Ta [mm] and each of arrangement pitches of the plurality of heat exchange members is represented by FP [mm], a relationship: Ta / Tf ≤ 5.6 × FP 1.3 is satisfied, characterised in that the main body portion includes an overlapping portion having a plate shape, which overlaps an outer peripheral surface of the heat transfer pipe , and overlapping portion is continuous with the extending portions , and wherein the extending portions and the overlapping portion form a heat transfer plate , and the heat transfer plate is a member separate from the heat transfer pipe . wherein each of the plurality of heat exchange members includes: a main body portion including a heat transfer pipe extending in a second direction intersecting with the first direction; and extending portions provided to the main body portion along the second direction, a main body portion including a heat transfer pipe extending in a second direction intersecting with the first direction; and extending portions provided to the main body portion along the second direction, wherein the extending portions extend from ends of the main body portion in a third direction intersecting with both of the first direction and the second direction, and wherein, when a dimension of the main body portion in the third direction is represented by La [mm], a dimension of the extending portions in the third direction is represented by Lf [mm], a dimension of a wall thickness of each of the heat transfer pipes is represented by tp [mm], and a thickness dimension of each of the extending portions is represented by Tf [mm], relationship: Tf ≤ tp is satisfied; and wherein, when a dimension of each of the main body portions in a direction orthogonal to both of the second direction and the third direction is represented by Ta [mm] and each of arrangement pitches of the plurality of heat exchange members is represented by FP [mm], a relationship: Ta / Tf ≤ 5.6 × FP 1.3 is satisfied, characterised in that the main body portion includes an overlapping portion having a plate shape, which overlaps an outer peripheral surface of the heat transfer pipe , and overlapping portion is continuous with the extending portions , and wherein the extending portions and the overlapping portion form a heat transfer plate , and the heat transfer plate is a member separate from the heat transfer pipe . <EOS>