Heat exchanger, heat exchange unit, and air conditioner

A heat exchanger that is included in an air conditioner comprises:

• a heat exchanger main body that extends in a first direction which intersects a vertical direction, and that has a heat transfer pipe and a plurality of fins which are attached to the heat transfer pipe, and
• a holder that is attached to one end of the first direction, on the heat exchanger main body,
• wherein
• the heat transfer pipe has
• a plurality of extension portions that extend in the first direction, and
• a plurality of fold portions that connect ends of pairs of the extension portions adjacent to one another in the first direction,
• the holder has
• a base located on one side of the first direction of the heat exchanger main body,
• a peripheral wall that protrudes to one side of the first direction, from an outside peripheral edge of the base, and
• at least one partition wall that partitions an inside of the peripheral wall in a second direction, that intersects a horizontal direction,
• a plurality of accommodations are formed so as to align in the second direction, using the base, the peripheral wall, and at least one partition wall,
• a through hole through which a fold portion out of the plurality of fold portions is inserted, is formed on each base on the plurality of accommodations,
• an inside edge of the through hole is disposed apart from the fold portion,
• said at least one partition wall includes a first partition wall, and
• at least one through portion that penetrates the first partition wall is formed on the first partition wall.