Heat exchanger

A heat exchanger mounted to a vehicle at a vehicle rear side of a wall body having a ventilation opening through which air flows to the vehicle rear side, the heat exchanger comprising:

• a core portion including a plurality of tubes in which a heat medium flows to exchange heat with air having passed through the ventilation opening of the wall body, the plurality of tubes being stacked in a tube stacking direction;
• a first header tank connected to one ends of the plurality of tubes to distribute the heat medium into the plurality of tubes, and being provided with an inflow port from which the heat medium flows into the first header tank;
• and
• a second header tank connected to the other ends of the plurality of tubes, into which the heat medium flowing through the tubes collects, wherein
• the core portion has an opening overlapping range that overlaps the ventilation opening at the vehicle rear side of the ventilation opening,
• the opening overlapping range is a partial range of the core portion in the tube stacking direction, and
• at least a part of the inflow port is arranged in an area of the first header tank corresponding to the opening overlapping range of the core portion in the tube stacking direction.