A heat exchanger comprising: a plurality of tubes in which refrigerant can flow; a fin (200, 300, 400) comprising tube couplers (211, 311, 411, 351, 451) in which the tubes are inserted, wherein the refrigerant exchanges heat with a fluid through the fin, the fin (200, 300, 400) comprising a first fin (210, 310, 410) coupled to a part of the tubes, the part of the tubes constituting a first row, and a second fin (250, 350, 450) provided on a side portion of the first fin and coupled to another part of the tubes, the another part of the tubes constituting a second row; a header coupled to at least one side portion of the tubes and distributing the refrigerant to the tubes; a drain part (230, 330, 430) disposed between the first and second fins, being configured to guide discharges of condensate water flowing on the first and second fins; and a guide part, provided on the first and second fins (210, 310, 410, 250, 350, 450), comprising at least one slope part (213, 216, 217, 416, 417), configured to guide condensate water flowing on a side portion of the fin, to the drain part (230, 430), wherein the guide part comprises: a recess part extending outward around at least one of the tube couplers and recessed a set depth; a first slope part configured to surround the recess part and inclined downwardly to the recess part; a second slope part (216, 416) disposed between the tube couplers (211, 411, 451) and inclined upwardly from a side end of the fin; a third slope part (217, 417) inclined downwardly from the second slope part; and a peak part formed between the second slope part and the third slope part, characterized in that the plurality of tubes are flat tubes; and in that the drain part (230, 330, 430) comprises a guide groove recessed downwardly between the second slope part of the first fin (210, 310, 410) and a second slope part of the second fin (250, 350, 450). a plurality of tubes in which refrigerant can flow; a fin (200, 300, 400) comprising tube couplers (211, 311, 411, 351, 451) in which the tubes are inserted, wherein the refrigerant exchanges heat with a fluid through the fin, the fin (200, 300, 400) comprising a first fin (210, 310, 410) coupled to a part of the tubes, the part of the tubes constituting a first row, and a second fin (250, 350, 450) provided on a side portion of the first fin and coupled to another part of the tubes, the another part of the tubes constituting a second row; a header coupled to at least one side portion of the tubes and distributing the refrigerant to the tubes; a drain part (230, 330, 430) disposed between the first and second fins, being configured to guide discharges of condensate water flowing on the first and second fins; and a guide part, provided on the first and second fins (210, 310, 410, 250, 350, 450), comprising at least one slope part (213, 216, 217, 416, 417), configured to guide condensate water flowing on a side portion of the fin, to the drain part (230, 430), wherein the guide part comprises: a recess part extending outward around at least one of the tube couplers and recessed a set depth; a first slope part configured to surround the recess part and inclined downwardly to the recess part; a second slope part (216, 416) disposed between the tube couplers (211, 411, 451) and inclined upwardly from a side end of the fin; a third slope part (217, 417) inclined downwardly from the second slope part; and a peak part formed between the second slope part and the third slope part, characterized in that the plurality of tubes are flat tubes; and in that the drain part (230, 330, 430) comprises a guide groove recessed downwardly between the second slope part of the first fin (210, 310, 410) and a second slope part of the second fin (250, 350, 450). a recess part extending outward around at least one of the tube couplers and recessed a set depth; a first slope part configured to surround the recess part and inclined downwardly to the recess part; a second slope part (216, 416) disposed between the tube couplers (211, 411, 451) and inclined upwardly from a side end of the fin; a third slope part (217, 417) inclined downwardly from the second slope part; and a peak part formed between the second slope part and the third slope part, characterized in that the plurality of tubes are flat tubes; and in that the drain part (230, 330, 430) comprises a guide groove recessed downwardly between the second slope part of the first fin (210, 310, 410) and a second slope part of the second fin (250, 350, 450).