A welding current source for supplying an electric welding current circuit with electric current and electric voltage for carrying out an electric welding process, wherein the welding current source is provided with a power conditioning device for conditioning electric current supplied to the welding current source for suitability in an electric welding process, wherein furthermore on a housing of the welding current source there are provided two pole contact devices, each of which protrude from the housing, and the welding current source is equipped with a cooling device, with which thermal heat loss released by the welding current source can be dissipated. In the case of such a welding current source and despite sufficient cooling of the electrical components, it shall be possible that the housing of the welding current source can be designed to be also smaller than before.