A heat exchanger includes flat tubes and fins. The fins are corrugated fins, and are disposed between the flat tubes that are vertically arranged. Between the vertically arranged flat tubes, heat transfer parts of each of the fins are arranged in the direction in which the flat tubes extend. Each of the heat transfer parts include louvers that extend in an up-and-down direction. Bent-out ends of the windward louvers include main edges, upper edges, and lower edges. The upper edges and the lower edges are tilted relative to the main edges. The tilt angle θ5 of the lower edges relative to the main edges is smaller than the tilt angle θ4 of the upper edges relative to the main edges.