An outdoor unit 2 of an air conditioner 1 includes: a cabinet 20 in which at least one air inlet and at least one air outlet are formed; a heat exchanger 7 arranged inside the cabinet 20; an air inlet hood 41 that covers the air inlet; and an air outlet hood 42 that covers the air outlet. The air inlet hood 41 includes: a facing panel 51 arranged facing the air inlet; an upper surface panel 53 arranged on an upper surface of a part between the air inlet and the facing panel 51; and two side panels 52 arranged respectively on two side surfaces of the part between the air inlet and the facing panel 51. A lower surface air intake hole 54 is provided to a lower surface of the part between the air inlet and the facing panel 51. A side surface air intake hole 55 is provided to at least one of the two side panels 52.