The cooling structure for a secondary battery has a first center exhaust duct and a second center exhaust duct arranged on a floor between the driver seat and the front passenger seat. Each exhaust duct is located between the bottommost face of the first battery pack and the vehicle floor to constitute a heat insulation layer. By employing this configuration, there can be provided a cooling structure for a secondary battery that is not affected by heat from an exhaust pipe located under the floor, even in the case where a battery pack is arranged between the driver seat and the front passenger seat.