In a heat exchanger, each of a plurality of heat exchange members includes: a main body portion including a heat transfer pipe; and extending portions provided to the main body. The extending portions extend from ends of the main body portion in a third direction. When a dimension of the main body portion in the third direction is represented by La, a dimension of the extending portions in the third direction is represented by Lf, a dimension of a wall thickness of each of the heat transfer pipes is represented by tp, and a thickness dimension of each of the extending portions is represented by Tf, relationships: Lf/La≥1 and Tf≤tp are satisfied.