A heat dissipation device includes a base, a fin group mounted on a top of the base, a fan mounted on a top of the fin group, a hollow fan duct mounted on the fan and a thermoelectric cooler secured on the fan duct. The thermoelectric cooler includes a cooling module having the Peltier effect and extending through a sidewall of the fan duct, and a heat sink enclosed by the fan duct and thermally contacting with the cooling module. The cooling module has a cold surface located at an inner side of the fan duct, and the heat sink thermally contacts with the cold surface of the cooling module. An airflow generated by the fan first flows through the heat sink and then reaches the fin group via the fan.