Since the ultrasonic vibration is generated by the welding head, and its energy is transferred from the welding head to the top block of the anvil, the closer the welding head is to the greater the energy, and the energy is transmitted from top to bottom, so when placing the wire, the thick The wire is placed at the bottom end, close to the welding head surface, and the thinner wires are arranged vertically upward in turn, so that the thick wire can obtain large energy, thereby preventing over-welding or insufficient welding. The vertical arrangement prevents side welding, thereby ensuring welding quality.