a tool changing device for a cutting head of a machine for cutting flat glass sheets , the tool changing device comprising : a bridge ; a carriage for supporting the cutting head , the carriage being slidingly attached to the bridge for translation along the bridge ; an electric motor that provides for translational motion of the carriage with respect to the bridge ; and a tool supporting slider , which is configured to support a plurality of tools such that the tools can be automatically exchanged between the tool supporting slider and the cutting head , the tool supporting slider coupled , by way of reversible fixing elements to the cutting head supporting carriage during work by the cutting head , and wherein the tool supporting slider is uncoupled from the cutting head supporting carriage during tool changing operations .