A cooling unit is configured to dissipate heat generated from a plurality of heat generation sections to a cooling medium by a plurality of heat dissipation sections, and the plurality of heat dissipation sections are provided corresponding to the plurality of heat generation sections respectively. The cooling unit includes: a first heat dissipation section that is provided corresponding to a first heat generation section among the plurality of heat generation sections, the first heat generation section having a smallest value of a heat dissipation performance index, the heat dissipation performance index being determined by dividing a temperature rise amount by a maximum heat generation amount of the heat generation section at maximum heat generation； a second heat dissipation section that is provided corresponding to a second heat generation section among the plurality of heat generation sections, the second heat generation section having a second smallest value of the heat dissipation performance index； a first flow path in which the first heat dissipation section is disposed and through which the cooling medium passes； and a second flow path in which the second heat dissipation section is disposed and through which the cooling medium passes, the second flow path being independent of the first flow path.
