The present invention relates to an outdoor heat exchanger and air conditioner in which the passage of a refrigerant is varied in an air cooling operation and an air heating operation. An outdoor heat exchanger according to an embodiment of the present invention includes a first header pipe configured to have a refrigerant, compressed by a compressor, to flow therein in the air cooling operation, a first heat exchange unit coupled to the first header pipe and configured to thermally exchange the refrigerant with air, a bypass pipe configured to have the refrigerant, thermally exchanged in the first heat exchange unit, to flow therein in the air cooling operation, a first distribution pipe coupled to the bypass pipe, a second header pipe configured to have the refrigerant, passing through the bypass pipe, to flow therein in the air cooling operation, a second heat exchange unit coupled to the second header pipe and configured to thermally exchange the refrigerant with air, a second distribution pipe configured to have the refrigerant, thermally exchanged in the second heat exchange unit, to flow therein in the air cooling operation, a second hot gas pipe configured to couple the compressor and the second distribution pipe, and a second hot gas control valve disposed in the second hot gas pipe to control a flow of the refrigerant.