A docking device used for attaching a portable electronic device thereon including a base, a lever, a button, and a locking member is provided. The lever pivoting in the base has a first end and a second end opposite to each other. The button and the locking member are movably disposed in the base respectively such that the button and the locking member are extruded out or hidden in the base respectively, wherein the button is located on a moving path of the first end, and the locking member is located on a moving path of the second end. When the portable electronic device is assembled to the docking device, the portable electronic device presses the button into the base to drive the first end, such that the second end drives the locking member out of the base to lock with the portable electronic device.