A heat dissipating device used for a PCB having a heat generating component includes a vapor chamber, a fin set, and a fixture. The vapor chamber is attached to the heat generating component. The fin set is connected above to the vapor chamber. The fixture is fixed to the PCB. The vapor chamber and the fin set are clamped between the fixture and the PCB. The fixture has a press plate which is pressed against a top of the fin set. Therefore, the press plate presses the vapor chamber without direct contact. That is, the applied pressure is concentrated on the fin set and then distributed evenly to the vapor chamber, which prevents deformation of the vapor chamber due to uneven pressure and further achieves the effect of the vapor chamber being attached smoothly to the heat generating component.