A heat sink for coolers is provided. The heat sink contains a heat conductive element, a heat dissipating shell covering over the heat conductive element, and a plurality of heat dissipating fins installed on the heat dissipating shell. The heat conductive element includes a heat conductive plate and a heat conductive block installed at the center thereof. The area of the bottom surface of the heat conductive block is greater than that of the topmost surface thereof. When the lower surface of the heat conductive plate is in contact with a device that needs heat dissipation, the heat conductive block increases the heat conducting volume at the center of the heat conductive plate, so that the heat produced by the device can be released at an optimal rate.