To provide a cooling device for air conditioner outdoor equipment which cuts down the power consumption during cooling and achieves economical electricity charges.

A first water storage tank 3 forming a cooling device includes: a first water storage space 300; and a drain hole 36 and is disposed on a top surface part 13 of an outdoor equipment body 1. The drain hole 36 opens at a bottom part 33 and communicates with the first water storage space 300. A second water storage tank 9 includes a second water storage space 94, is disposed on a location other than the top surface part 13, and is connected with the first water storage tank 3 so as to enable water conduction therebetween. A cooling part 4 includes a base part 41 and a water retention part 42 and is attached to the side of an air intake port 12. The water retention part 42 is made of a porous material, is attached to the base part 41, and has a vent hole 43. A water permeable sheet 5 is made of a porous material and is placed on the top surface part 13 in a state that an upper surface faces the drain hole 36 and directly contacts with an outer surface of the bottom part 33. One end side of the water permeable sheet 5 contacts with the water retention part 4 at the side of the air intake port 12.