A heat dissipation device includes a base, fins and strip-shaped plates. The fins protrude side by side from the base, and the fins respectively include first end edges and second end edges opposite to each other. The first end edges are connected to the base. The strip-shaped plates are parallel to the base and connected to at least a part of the second end edges of the fins, and strip-shaped openings are formed between the strip-shaped plates. The base, the fins and the strip-shaped plates collectively surround chambers in a non-closed manner, and each of the strip-shaped openings is connected to the corresponding chamber. A distance between two adjacent fins of the fins is S, a width of any one of the strip-shaped openings is d, and d/S is between 0.01 and 0.4. |