A secure device for a heat sink includes a frame and a plurality of cylindrical posts. The frame provides a plurality of elongated projections at the inner side thereof. Each of the cylindrical posts is attached to the outer side of the frame. A plurality of split portions are provided at the upper end of the respective cylindrical post. A reversed deep countersink is provided in the cylindrical post and an engaging piece is disposed at the inner side of the respective split portion. A wedge locator is disposed at one of the split portions corresponding to a lateral side of the heat sink such that the heat sink is capable of being elastically secured with the wedge locator and the elongated projections.