A heat dissipator includes a plate-shaped base portion that extends in a first direction along a direction where a refrigerant flows and in a second direction orthogonal to the first direction and has a thickness in a third direction, and fins that protrude from the base portion to one side in the third direction, extend in the first direction, are arranged in the second direction, and guide the refrigerant. A second of the fins is provided continuously on one side in the first direction that is a downstream side of a first of the fins, and a third fin that is provided continuously on another side in the first direction of the first fin, and includes an end on the one side in the third direction on the other side in the third direction.