The present invention provides a heat dissipating device combined structure, which consists of a heat sink and a clasp member. At least one expanded portion extends from the heat sink, and a side extends from each of the two sides of a base of the clasp member to form a conduit. The heat sink and a circuit board are disposed inside the conduit, and at least one ledge portion is formed on the sides. Moreover, a slanting portion extends from and is provided on air foils configured on the sides, and the ends of the slanting portions respectively clasp the expanded portions. Accordingly, the circuit board is mounted on the ledge portions, and electronic components on the circuit board are attached to the bottom portion of the aforementioned heat sink.