A heat exchanger (10,10A,10C) comprising: a plate-like fin having one end side and an other end side in a first direction (x); and being provided with through holes; a first heat transfer tube and a second heat transfer tube that each extend through one of said through holes of the fin and that are adjacent to each other in a second direction (z) crossing the first direction, wherein an outer shape of each of the first heat transfer tube and the second heat transfer tube in a cross section perpendicular to an extending direction (y) of each of the first heat transfer tube and the second heat transfer tube is a flat shape having a long side direction and a short side direction, a first end portion of the first heat transfer tube located at the one end side is disposed at one side in the second direction relative to a second end portion of the first heat transfer tube located at the other end side, a third end portion of the second heat transfer tube located at the one end side is disposed at the one side in the second direction relative to a fourth end portion of the second heat transfer tube located at the other end side, a portion to which the fin and at least one of the first heat transfer tube and the second heat transfer tube are connected, and at least one clearance portion that separates between the fin and the at least one of the first heat transfer tube and the second heat transfer tube are disposed between the fin and the at least one of the first heat transfer tube and the second heat transfer tube, the at least one clearance portion is disposed at the one end side in the first direction relative to an imaginary center line (L2a) that passes through a center of the first heat transfer tube in the long side direction and that extends along the short side direction, wherein the at least one clearance portion (4 1a) is disposed to overlap with a first imaginary line segment (L1a) that connects between the first heat transfer tube and the second heat transfer tube in a shortest distance and that is drawn at the most one end side in the first direction, and the at least one clearance portion is formed as a through hole being continuous to a respective through hole of the plate-like fin. a plate-like fin having one end side and an other end side in a first direction (x); and being provided with through holes; a first heat transfer tube and a second heat transfer tube that each extend through one of said through holes of the fin and that are adjacent to each other in a second direction (z) crossing the first direction, wherein an outer shape of each of the first heat transfer tube and the second heat transfer tube in a cross section perpendicular to an extending direction (y) of each of the first heat transfer tube and the second heat transfer tube is a flat shape having a long side direction and a short side direction, a first end portion of the first heat transfer tube located at the one end side is disposed at one side in the second direction relative to a second end portion of the first heat transfer tube located at the other end side, a third end portion of the second heat transfer tube located at the one end side is disposed at the one side in the second direction relative to a fourth end portion of the second heat transfer tube located at the other end side, a portion to which the fin and at least one of the first heat transfer tube and the second heat transfer tube are connected, and at least one clearance portion that separates between the fin and the at least one of the first heat transfer tube and the second heat transfer tube are disposed between the fin and the at least one of the first heat transfer tube and the second heat transfer tube, the at least one clearance portion is disposed at the one end side in the first direction relative to an imaginary center line (L2a) that passes through a center of the first heat transfer tube in the long side direction and that extends along the short side direction, wherein the at least one clearance portion (4 1a) is disposed to overlap with a first imaginary line segment (L1a) that connects between the first heat transfer tube and the second heat transfer tube in a shortest distance and that is drawn at the most one end side in the first direction, and the at least one clearance portion is formed as a through hole being continuous to a respective through hole of the plate-like fin.