Provided is a heat exchanger, which includes a plurality of flat tubes in which refrigerant flows, a fin including tube couplers in which the flat tubes are inserted, wherein the refrigerant exchanges heat with a fluid through the fin, and a header coupled to at least one side portion of the flat tubes and distributing the refrigerant to the flat tubes. The fin includes a first fin coupled to a part of the flat tubes, the part of the flat tubes constituting a first row, and a second fin provided on a side portion of the first fin and coupled to another part of the flat tubes, the another part of the flat tubes constituting a second row.