PURPOSE: To provide a cooling device for vehicle electrical equipment, which enhances the heat releasing property of a relay box and the like and thus reduces the accumulation of heat.

CONSTITUTION: In a vehicle in which an engine room 11 is equipped with electrical equipment such as a relay, an opening is formed in part of a relay box 22 enclosing such electrical equipment, and the inside of the relay box 22 is communicated with the upstream of an air cleaner 15. Therefore, when the engine is started, heat in the relay box 22 connected to the air cleaner 15 is sucked toward the air cleaner by the intake negative pressure of the engine. The relay, etc., that is incorporated into the relay box is thus cooled.