A heat dissipation device includes a base seat having a first chamber. The first chamber has multiple partitioning sections to partition the first chamber into multiple rooms without communicating with each other. A first working fluid is disposed in the rooms. Multiple two-phase fluid radiating fins are disposed on upper side of the base seat. Each of the two-phase fluid radiating fins is formed with an internal second chamber in communication with the rooms or not in communication with the rooms. The heat dissipation device can achieve better heat dissipation effect.