A heat dissipation device for dissipating heat generated from an add-on card. The heat dissipating device includes two heat sinks and two heat pipes connecting with the two heat sinks. Each of the heat sinks includes a base and a fin group mounted on a top surface of the base. Each of the heat pipes includes a connecting section and two heat-conductive sections extending from opposite ends of the connecting section. One of the two heat-conductive sections of each of the heat pipes is sandwiched between the base and the fin group of one heat sink, and another of the two heat-conductive sections is sandwiched between the base and the fin group of another heat sink.