The welding jigs are designed for the welding of spatial elements of vehicle bodies using manual welding guns. They ensure the positioning and the pneumatic clamping of welded elements with the required accuracy. By communicating with the welding machine, the control system of the welding jig provides the control of the presence of all the welded details, automatic choice of the proper welding process on the welding machine as well as the control of the execution of the pre-set number of welds.