A clamping device for clamping a hard disk drive includes a supporting frame and a spacing member. The supporting frame includes a connection board, a fixing arm, and a spacing arm. The fixing arm and the spacing arm extend from opposite ends of the connection board in a direction away from the connection board. The connection plate, the fixing arm, and the spacing arm cooperatively define a receiving space for receiving the hard disk drive. The spacing arm includes an internal surface facing the receiving space and an external surface opposite to the internal surface. The spacing member includes two elastic elements. The spacing member is arranged on the external surface, with portions of the elastic elements protruding out of the external surface.