A heat exchanger, comprising: a heat exchange unit in which heating medium flow channels through which a heating medium flows in a space between a plurality of plates and combustion gas flow channels through which a combustion gas combusted in a burner in a combustion chamber flows are alternately formed to be adjacent to each other, wherein the heat exchange unit is configured with a sensible heat unit configured to surround an outer side of the combustion chamber, configured with an area at one side of each one of the plates, and configured to heat the heating medium using sensible heat of the combustion gas generated by the combustion in the burner; and a latent heat unit configured with an area at the other side of each one of the plates and configured to heat the heating medium using latent heat of water vapor contained in the combustion gas which undergoes heat exchange in the sensible heat unit, and a flow channel cap is coupled to a rear side of the sensible heat unit and configured to provide a flow channel of the combustion gas to allow a combustion gas which passes through a combustion gas flow channel formed at an upper portion of the sensible heat unit to flow into a combustion gas flow channel of the latent heat unit, the heat exchanger characterized by further comprising a plurality of first combustion gas flow holes that are formed at the upper portion of the sensible heat unit to allow the combustion gas generated in the combustion chamber to flow to a combustion gas bypass flow channel formed between the sensible heat unit and the flow channel cap, and a plurality of second combustion gas flow holes that are formed at a lower portion of the sensible heat unit to allow the combustion gas which passes through the combustion gas bypass flow channel to flow to the combustion gas flow channel of the latent heat unit. a heat exchange unit in which heating medium flow channels through which a heating medium flows in a space between a plurality of plates and combustion gas flow channels through which a combustion gas combusted in a burner in a combustion chamber flows are alternately formed to be adjacent to each other, wherein the heat exchange unit is configured with a sensible heat unit configured to surround an outer side of the combustion chamber, configured with an area at one side of each one of the plates, and configured to heat the heating medium using sensible heat of the combustion gas generated by the combustion in the burner; and a latent heat unit configured with an area at the other side of each one of the plates and configured to heat the heating medium using latent heat of water vapor contained in the combustion gas which undergoes heat exchange in the sensible heat unit, and a flow channel cap is coupled to a rear side of the sensible heat unit and configured to provide a flow channel of the combustion gas to allow a combustion gas which passes through a combustion gas flow channel formed at an upper portion of the sensible heat unit to flow into a combustion gas flow channel of the latent heat unit, the heat exchanger characterized by further comprising a plurality of first combustion gas flow holes that are formed at the upper portion of the sensible heat unit to allow the combustion gas generated in the combustion chamber to flow to a combustion gas bypass flow channel formed between the sensible heat unit and the flow channel cap, and a plurality of second combustion gas flow holes that are formed at a lower portion of the sensible heat unit to allow the combustion gas which passes through the combustion gas bypass flow channel to flow to the combustion gas flow channel of the latent heat unit.