A heat dissipation apparatus suited for dissipating heat of a heat source. The heat dissipation apparatus includes a tank, a heat-insulation unit and a pipe. The tank has an outlet end, an inlet end and an accommodating space, wherein the tank receives heat of the heat source from above. The heat-insulation unit is disposed in the accommodating space of the tank, and the heat-insulation unit includes a heat-insulation nozzle. The heat-insulation nozzle has a first opening, a second opening and a neck portion, wherein the first opening communicates with the inlet end, the second opening communicates with the accommodating space and the neck portion is near the second opening. The pipe communicates the outlet end and the inlet end and forms a closed circulating loop with the tank.