A heat dissipation device includes a conductive plate and a fastener. The fastener includes a fastening element and an elastic element coiled around the fastening element. The fastening element includes a pole portion and a head portion formed at one end of the pole portion. The conductive plate defines a supporting portion through the conductive plate. The supporting portion defines a hole, an upper groove and a lower groove communicating with one another. The upper groove and the lower groove are coaxial with each other. A flange protrudes from a circumference of the pole portion. The pole portion enters the upper groove. The flange abuts a bottom of the conductive plate and is received in the lower groove. The elastic element elastically abuts the top of the conductive plate.