HEAT EXCHANGER AND AIR CONDITIONING DEVICE IN WHICH SAME IS USED

A heat exchanger includes a plurality of flat tubes extending in a first direction and arranged with spacing from each other in a second direction, and a header extending in the second direction and connecting end portions of the adjacent flat tubes of the plurality of flat tubes in the first direction. A flow passage provided inside the header includes a plurality of partition portions each provided between the adjacent flat tubes and configured to block at least a part of the flow passage between the adjacent flat tubes, a plurality of insertion portions formed between the adjacent partition portions and into which the plurality of flat tubes are inserted, a first communication passage allowing one ends of the adjacent insertion portions to communicate with each other, and a second communication passage allowing an other ends of the adjacent insertion portions to communicate with each other. A cross-sectional area of the first communication passage, of a cross-section perpendicular to the second direction is larger than a cross-sectional area of the second communication passage, of a cross-section perpendicular to the second direction, and the first communication passage is provided with a first refrigerant inlet connected to the flow passage and allowing the refrigerant flow into the header. Thus, a heat exchanger performance can be improved by reducing a refrigerant pressure loss and by achieving uniform distribution of the refrigerant.