Heat exchanger and air-conditioning apparatus

A heat exchanger comprising a plurality of heat transfer tubes arranged in a first direction, each of the plurality of heat transfer tubes extending in a second direction intersecting the first direction, each of the plurality of heat transfer tubes having both end portions in the second direction sealed, the plurality of heat transfer tubes being configured to allow refrigerant to flow therethrough, wherein

• each of the plurality of heat transfer tubes has a plurality of through holes formed at positions inward of the both end portions, the plurality of through holes allowing an outside and an inner space of each of the plurality of heat transfer tubes to be in communication,
• the plurality of heat transfer tubes include a plurality of coupling units or a plurality of header pipes, the plurality of coupling units being configured to directly couple the plurality of through holes of adjacent heat transfer tubes from among the plurality of heat transfer tubes, the plurality of header pipes being inserted into the plurality of through holes, and being configured to couple the plurality of through holes of adjacent heat transfer tubes from among the plurality of heat transfer tubes,
• the plurality of coupling units or the plurality of header pipes constitute a plurality of header units formed to extend in the first direction, each of the plurality of header units allowing refrigerant communication between the inner spaces of the plurality of heat transfer tubes, and forming a refrigerant inlet/outlet of a heat transfer tube group constituted of the plurality of heat transfer tubes, and
• the plurality of header units are provided at a position that divides the plurality of heat transfer tubes into an upper portion and a lower portion in a gravity direction.