A cooling device comprises a cooler, a connecting piece and a fixing piece, wherein the connecting piece is used for fixing the cooler on a bearing piece; the fixing piece is used for fixing the connecting piece on the cooler; the connecting piece comprises a connecting section and an extending section; the cooler is provided with a containing hole and an installation hole communicated with the containing hole; the extending section is located on the outer side of the cooler and is used for being matched with the bearing piece; the connecting section is arranged and contained in the containing hole in a penetrating mode; the fixing piece penetrates through the installation hole and is matched with the connecting piece, and the periphery of the fixing piece abuts against the cooler, so that the connecting piece is fixed to the cooler. As the connecting section arranged in the containing hole of the cooler in the penetrating mode is fixed to the cooler through the fixing piece, the technical problems that the cost is over high due to nickel plating on the cooler and the performance of the cooler is not stable due to unfirm welding are avoided.