What is disclosed is a heat exchanger including: a core including a plurality of core plates, first and second passages, and a vertical passage; a base plate including a passage port; and a distance plate; wherein the first vertical passage and the passage port are arranged apart from each other in a direction orthogonal to a stacking direction of the core plates, and wherein the distance plate includes a bottom wall part and a swelling part, the bottom wall part being a thin plate-shaped and being joined to an upper surface of the base plate, the swelling part swelling up in the stacking direction from the bottom wall part so as to surround a circumference of a communication passage which communicates the first vertical passage with the passage port and being joined to a lowermost surface of the core in a flange part of a tip of the swelling part.