Abstract: The invention relates to a device for welding workpieces that have a large cross-sectional area, as well as for cases of high welding power requirements. The device in accordance with the invention comprises a mechanism for continuously displacing the workpieces being welded with a controlled drive, a mechanism for imparting to the workpieces additional reciprocating motion, a welding transformer, and a means for controlling the speed of the drive. The drive speed control means includes a welding-current pulse shaper coupled to the output of a current transformer, the latter being included in the primary circuit of the welding transformer and a welding-current pulse-length setter. The latter and the output of the pulse shaper are coupled to a comparator, the output whereof is coupled to the drive control circuit.