A device for changing the electrode of an electrode-holder tool of a welding device, with a first part configured to house an electrode-holder tool and including means to prevent the electrode-holder tool from moving, and a second part installed around the first part and covering the part of the electrode protruding outside the first part, where the second part can be separated from the first part by sliding along the electrode, and is able to rotate relative to the fixed part when it surrounds it, and where the second part is configured to tighten or untighten the mandrel and to attach the electrode and the second part, enabling it to be removed from the mandrel when the first part and the second part are separated.