We have developed non-equilibrium simulation model of GTA. In this paper, simulation results of plasma property of argon GTA at atmospheric pressure are presented and, furthermore, the reliability of the simulation model is evaluated. As a result, it was revealed that non-equilibrium characteristic appears in regions close to both electrodes and the fringe of the arc column where the temperatures decrease below approximately 10000K. It was also found that non-equilibrium region near the anode surface has thickness of 0.3mm. This result agrees with the simulation result predicted with one-dimensional electrical sheath model.