Power supply unit and cooling method

A power supply unit, which comprises one or more power supply circuits generating an electric current and an air blower unit for forcibly generating airflow for cooling the power supply circuit, is covered by a cover. The adopted cover is one in which formed are an intake taking in the air for generating airflow by the air blower unit, a path for guiding the airflow exhausted from the power supply unit main body by the air blower unit by changing direction of the airflow to upward, and an outlet for externally exhausting the air flowing along the path. This configuration enables the exhaust of air in a desirable manner for the power supply unit or the place for putting the unit.