The invention relates to a stud welding device comprising a central stud welding unit (3) having a welding exit (17) and a control terminal (23), and comprising at least one external control unit (5). Said control unit is connected to a welding entry (21), to the welding exit (17) of the central stud welding unit (3), and to a control terminal (27) with a control terminal (23) of the central stud welding unit (3). In addition, the control unit comprises at least one welding exit (31) which can be connected to a stud welding head (7). The external control unit (5) comprises at least one controllable switch (29) which connects the welding entry (21) of the control unit (5) to a welding exit (31) in a selectable manner.