Heat exchanger

A heat exchanger comprising:

• a plurality of heating medium channels (P1) formed in a space between a pair of plates facing each other and through which a heating medium flows;
• a plurality of combustion gas channels (P2) formed at an outer side of the plurality of heating medium channels (P1) and through which a combustion gas combusted in a burner flows;
• a plurality of heating medium dispersion portions (123 and 153) in which opened portions (123′ and 153′) and blocked portions (123″ and 153″) are formed at an inlet portion through which the heating medium flows into the plurality of heating medium channels (P1) or an outlet portion through which the heating medium flows out from the plurality of heating medium channels (P1);
• and
• a heat exchange part in which the plurality of heating medium channels (P1) and the plurality of combustion gas channels (P2) are alternately formed adjacent to each other in a space between a plurality of plates,
• wherein the heat exchange part is configured to surround an outer side of a combustion chamber (C) provided at a central portion of the heat exchange part, and a plurality of the heat exchange part is provided in a stacked structure;
• and
• the plurality of heating medium dispersion portions (123 and 153) are provided at a channel in which the flow direction of the heating medium is switched in the plurality of heat exchange parts.