Cooling construction of a heat-generating element

A cooling structure includes a plurality of plate-shaped heat-generating elements (16, 19-21) such as battery parts (16), DC-DC converters (19, 20) and an electrical element (eg, relay 21). In the cooling structure, the heat generating elements are arranged in a plate thickness direction so as to have predetermined intervals for forming fluid passages (24, 27, 32) respectively provided between adjacent heat generating elements, and the fluid passages are provided to be allow a fluid to pass through to cool the heat generating elements. Accordingly, all the heat-generating elements can be effectively cooled while the cooling structure can be made compact.