The study presents the results of tests of welding arc electromagnetic radiation in TIG method. Within the research it was necessary to carry out an extensive overview of reference publications about arc radiation and applied testing methods. Taking advantage of an arc model in TIG method described in reference publications it was possible to determine a dependence of welding current intensity and welding arc length on the intensity of welding arc visible radiation. The research-related tests made it possible to determine new parameter values in the generalised arc model for a 2÷5-mm range of welding arc length, which resulted in better matching of a model. It was also possible to demonstrate that an increase in welding current intensity for a constant length of a welding arc causes an increase in the intensity of arc visible radiation and that the same effect can be obtained by increasing an arc length at constant welding current intensity. The research also led to a conclusion that the monitoring of welding arc visible radiation in TIG method can be used for controlling an arc length.