Since gas tungsten arc (GTA) can stabilize a high-temperature arc plasma by employing shielding gas, it is used as a heat source device. It has high heating efficiency and highly controllable characteristics and requires low cost for equipment investment. Therefore, it is widely utilized, for example, for production of nanoparticles, material processing, detoxification of toxic waste, and so on. A numerical simulation model is a useful tool to evaluate the heat source property of GTA. Simulated images of temperature distributions of GTA considering the nonequilibrium effect are presented.