This refrigeration cycle apparatus is configured such that a mixed refrigerant including HFO-1123 or HFO-1123 is used as a refrigerant, and at least one of a first heat exchanger and a second heat exchanger has a plurality of fins and a plurality of flat tubes in which a plurality of channels through which the refrigerant flows are formed, wherein the plurality of flat tubes satisfy the relationship in which 0.9 mm ≤ DA ≤ 3.0 mm, where DA is the width of the flat tube.
