This invention provides welding torch for gas shielded welding on MIG, which comprises ceramic spray nozzle 1 hard to burn loss at high temperature, swan neck base 3 with low whole resistance for less caloricity that can make good use of cooling function of build-in high heat-efficiency exchanger 302, ignition tip 2 with ceramic cover 202 to prevent the direct radiation from electric arc, wire-feeding soft pipe 5 with soft front end to prevent excessive bending and instability. The improvement enhances welding torch proper and fits particularly to CO2 welding with great current or abundant argon.