A cooling device for a vehicle is configured as a thermosiphon that performs heat transfer by a working fluid sealed in a sealed container to cool a target object. The cooling device includes an evaporator and an outdoor condenser. The evaporator forms a part of the sealed container, and evaporates the working fluid by absorbing heat of the target device. The outdoor condenser forms a part of the sealed container, and is disposed above the evaporator. The outdoor condenser is located adjacent to a cabin space with respect to a vehicle body around the cabin space. The outdoor condenser is fixed to the vehicle body or a member provided adjacent to the cabin space with respect to the vehicle body, and condenses the working fluid by radiating heat of the working fluid vaporized in the evaporator to an outside air.