A cooling device of the invention includes a flow channel configured so that a coolant passes, a plurality of heat receiving portions configured so that heat generated by a plurality of heat generating portions arranged along one side surface of the flow channel outside the flow channel is transferred, a plurality of heat radiating portions arranged in the flow channel, and a plurality of heat transferring portions configured to connect the heat receiving portions and the heat radiating portions and transfer heat between the heat receiving portions and the heat radiating portions; the flow channel is divided into a first flow channel arranged in close proximity to the one side surface and a second flow channel arranged with the first flow channel sandwiched between the one side surface and the second flow channel; and the heat radiating portions include one or a plurality of first heat radiating portions arranged in the first flow channel and one or a plurality of second heat radiating portions arranged in the second flow channel.