A vehicle battery cooling device including a battery case containing a battery for generating a high voltage and disposed in a space between a pair of right and left side panels at a rear side of a vehicle, a cooling fan disposed at a location overlapping the battery case in a vertical direction of the vehicle and configured to send cooling air to the battery case, and a duct placed in a space between the battery case and the side panels in a width direction of the vehicle so as to communicate the cooling fan and the battery case with each other. The duct is fastened to the battery case via a bracket, the bracket has an inner space having a U-shaped cross section, and the duct is disposed inside the inner space.