A heat exchanger comprising: a first stack portion including a plurality of plates (111a to 111f) which are stacked, a first refrigerant passage and a first coolant passage which are formed between the plurality of plates (111a to 111f); a second stack portion including a plurality of receiver components which are stacked and a refrigerant retaining portion leading to the first refrigerant passage and being formed in the plurality of receiver components, the second stack portion being stacked on the first stack portion in a same direction as a stacking direction in which the plurality of plates are stacked; a third stack portion for subcooling, including a plurality of subcool plates (131a to 131d) which are stacked and a second refrigerant passage for subcooling and a second coolant passage for subcooling which are formed between the plurality of subcool plates(131a to 131d), the third stack portion being further stacked on the second stack portion in a same direction as a stacking direction in which the first stack portion and the second stack portion are stacked, characterised in that each of the plurality of receiver components has a window frame shape provided with a central hole, and the stacked plurality of receiver components constitute a side of the refrigerant retaining portion, one of the plurality of plates, closest to the second stack portion, of the first stack portion serves as an upper surface of the refrigerant retaining portion, and one of the plurality of subcool plates, closest to the second stack portion, of the third stack portion serves as a lower surface of the refrigerant retaining portion. a first stack portion including a plurality of plates (111a to 111f) which are stacked, a first refrigerant passage and a first coolant passage which are formed between the plurality of plates (111a to 111f); a second stack portion including a plurality of receiver components which are stacked and a refrigerant retaining portion leading to the first refrigerant passage and being formed in the plurality of receiver components, the second stack portion being stacked on the first stack portion in a same direction as a stacking direction in which the plurality of plates are stacked; a third stack portion for subcooling, including a plurality of subcool plates (131a to 131d) which are stacked and a second refrigerant passage for subcooling and a second coolant passage for subcooling which are formed between the plurality of subcool plates(131a to 131d), the third stack portion being further stacked on the second stack portion in a same direction as a stacking direction in which the first stack portion and the second stack portion are stacked, characterised in that each of the plurality of receiver components has a window frame shape provided with a central hole, and the stacked plurality of receiver components constitute a side of the refrigerant retaining portion, one of the plurality of plates, closest to the second stack portion, of the first stack portion serves as an upper surface of the refrigerant retaining portion, and one of the plurality of subcool plates, closest to the second stack portion, of the third stack portion serves as a lower surface of the refrigerant retaining portion.