A heat exchanger includes a heat exchanging section for performing heat exchange between a refrigerant and a cooling medium and a passage section. The passage section includes a first passage and a second passage for supplying the refrigerant to the heat exchanging section and a supply passage for supplying the refrigerant to the first passage and the second passage. The first passage and the second passage define a first opening portion and a second opening portion opening at an end of the supply passage. A minimum distance between an opening edge of the first opening portion and an inner surface of the supply passage is equal to a minimum distance between an opening edge of the second opening portion and the inner surface of the supply passage.