A heat dissipating device for cooling a number of electronic devices, includes a heat sink assembly (10) and a fan (20) mounted to a side of the heat sink assembly. The heat sink assembly includes a heat spreader (12), a plurality of fins (14), and heat pipes thermally connecting the heat spreader and the fins. The fins form a plurality of channels (140) therebetween, and include a guiding fin (15). The guiding fin includes a body (150) spaced from the heat spreader and an inclined sidewall (152) bent from the body. An airflow generated by the fan has a portion flowing through the channels of the fins and another portion flowing between the body and the heat spreader for blowing a second heat generating electronic device by guiding of the sidewall of the guiding fin.