A heat exchanger (10; 10a, 10b) comprising: a plurality of tubes each having a flowpath through which a refrigerant flows; and a corrugated fin including a plurality of heat transfer walls that are arranged in a running direction of the tubes and span from one to the other of adjacent tubes among the plurality of tubes, the fin being capable of exchanging heat with the tubes, the heat transfer walls that are arranged in a running direction of the tubes and span from one to the other of adjacent tubes among the plurality of tubes defining an arrangement of heat transfer walls, wherein the heat transfer walls each include: a first heat transfer piece leading to a first edge portion positioned on an upwind side of a passing airflow; and a second heat transfer piece leading to a second edge portion indented relative to the first edge portion toward a downwind side in a direction of the airflow, wherein the first edge portion and the second edge portion are both arranged on the upwind side of the airflow, and wherein the first heat transfer piece is disposed at least on every other layer of the arrangement of heat transfer walls on both of a side closer to one tube and the second heat transfer piece is disposed at least on every other layer of the arrangement of heat transfer walls on both of a side closer to the other tube of adjacent tubes among the plurality of tubes such that first heat transfer piece and the second heat transfer piece appears alternately on both sides, and wherein a first fin pitch at a predetermined area on the upwind wide is set wider than a second fin pitch at an area on the downwind side relative to the predetermined area, and characterized in that the first heat transfer piece and the second heat transfer piece are provided not to overlap with each other as seen in a vertical direction. a plurality of tubes each having a flowpath through which a refrigerant flows; and a corrugated fin including a plurality of heat transfer walls that are arranged in a running direction of the tubes and span from one to the other of adjacent tubes among the plurality of tubes, the fin being capable of exchanging heat with the tubes, the heat transfer walls that are arranged in a running direction of the tubes and span from one to the other of adjacent tubes among the plurality of tubes defining an arrangement of heat transfer walls, wherein the heat transfer walls each include: a first heat transfer piece leading to a first edge portion positioned on an upwind side of a passing airflow; and a second heat transfer piece leading to a second edge portion indented relative to the first edge portion toward a downwind side in a direction of the airflow, a first heat transfer piece leading to a first edge portion positioned on an upwind side of a passing airflow; and a second heat transfer piece leading to a second edge portion indented relative to the first edge portion toward a downwind side in a direction of the airflow, wherein the first edge portion and the second edge portion are both arranged on the upwind side of the airflow, and wherein the first heat transfer piece is disposed at least on every other layer of the arrangement of heat transfer walls on both of a side closer to one tube and the second heat transfer piece is disposed at least on every other layer of the arrangement of heat transfer walls on both of a side closer to the other tube of adjacent tubes among the plurality of tubes such that first heat transfer piece and the second heat transfer piece appears alternately on both sides, and wherein a first fin pitch at a predetermined area on the upwind wide is set wider than a second fin pitch at an area on the downwind side relative to the predetermined area, and characterized in that the first heat transfer piece and the second heat transfer piece are provided not to overlap with each other as seen in a vertical direction.