Negative electrode holder of spot welder

The utility model relates to a negative electrode holder of a spot welder, which comprises an outer shell with a small hole. A strong magnet whose inner part is provided with a big hole is arranged under the outer shell. The position of the small hole is sheathed with a sleeve barrel. Screws, spacers, spring, etc. are upwards penetrated through the bottom of the big hole. An extension block is screwed on a screw. A cross hole is arranged on th extension block. Electric wires are combined at the middle of the cross hole. The spacers, joints, the screws, etc. are arranged on extension blocks, wherein, the elctric wires can be arranged on the joints. When the utility model is used, a strong magnet attaches a bent welding piece to be welded. The utility model is also suitable for a thicker welding piece to be welded.