PURPOSE: An automatic welding method is provided to tightly bond the object to be welded by a more accurate welding line trace using the filtering welding current value obtained by the Kalman filtering method for the line trace. CONSTITUTION: An automatic welding using a welding robot comprises the steps:comparing the real welding current value with the presumptive welding current value and obtaining the mutual difference value; obtaining the filtering welding current value using the Kalman filtering method for sampling the welding current value by calculating the Kalman Gain; and bonding the material to be welded using the obtained filtering welding current value for tracing the welding wire.
