A heat dissipating device for a heat generating component mounted on a frame-shaped carrier, includes a heat sink block, and a base having a top surface and a bottom surface. The heat sink block is mounted on the top surface of the base. A coupling board is formed on each of two opposite sides of the base at a position close to the bottom surface and lower in height than the top surface of the base. The coupling board is formed with an installing portion for being coupled to a coupling portion of the frame-shaped carrier, so as to fix the base to the frame-shaped carrier via the coupling board and allow the bottom surface of the base to cover the heat generating component on the frame-shaped carrier, to thereby make the heat sink block have a maximum heat dissipating area to dissipate heat generated by the heat generating component.