A superior slim type of speaker comprises: a baffle, a hole being disposed at a center of the baffle, an vibrating system being disposed at an inner edge of the hole; a voice coil, a periphery of a bottom surface of the vibrating system being connected to a top edge of the voice coil, an outer edge of the voice coil being set a coil, the voice coil being adjacent to two sides of an outer edge of the coil, and the two sides being connected to two lead wires respectively; and a U-type iron member, a loop groove is disposed at a top periphery of the U-type iron member, two sides of the U-type iron member has two gaps respectively, and at least one side of each of the two gaps has an isolating portion; wherein when the U-type iron member is disposed at a bottom of the baffle, the voice coil is elongated to the loop groove in order to let the lead wires outwardly pass through the gaps and be upwardly fastened at a bottom surface of the baffle. As a conclusion, the distance between the lead wires and the U-type iron member are not necessarily considered, so that the length of the voice coil is shortened and the thickness of the whole speaker is decreased as well.