A cooling device includes: a case that includes a supply port for supplying coolant to an interior of the case and a discharge port for discharging coolant at the interior of the case to an exterior of the case; plural fins that each have a plate shape, that are provided an exterior of at separations along their plate thickness direction, and that have coolant flowing between adjacent fins; projecting portions that are respectively formed at the fins, that project out along the plate thickness direction of the fins, and that abut adjacent fins; and restraining members that are respectively inserted through insertion holes respectively formed in the fins, that pierce through the plural fins, and that restrain relative movement between adjacent fins.