To provide an outdoor unit of an air conditioner in which generation of abnormal noise is prevented by changing an air flow between a support column standing at a corner part of a heat exchanger room and a heat exchanger.

In the outdoor unit of the air conditioner, the support column 9 is provided to stand at the corner part 8 between a bottom plate 3 and a top plate installed in parallel with this to face to a bending part 6a of the heat exchanger 6. The support column 9 includes a back surface support part 9a arranged nearly in parallel with a back surface, a side surface support part 9b arranged nearly in parallel with one side surface, a corner surface support part 9c for connecting a corner between the back surface support part 9a and the side surface support part 9b, a back surface folded part 9d folded to the inside from the back surface support part 9a, and a side surface folded part 9e folded to the inside from the side surface support part 9b. A plurality of ventilation holes 10 are formed on at least the back surface support part 9a and the side surface support part 9b.