A cooling device for a high voltage electrical unit for a motor of a vehicle, includes: an inverter for controlling the motor that drives the vehicle; an electrical energy storing device for supplying electrical energy to the motor via the inverter; a downverter for decreasing source voltage of the electrical energy storing device, the downverter, the inverter, and the electrical energy storing device disposed under a seat of the vehicle in a concentrated manner; a fan, disposed under the seat, for moving cooling air to the electrical energy storing device and the inverter; an air inlet disposed under the seat and at an end of the seat as viewed in a width direction of the vehicle; and an air outlet disposed under the seat and at the other end of the seat as viewed in a width direction of the vehicle.