The invention relates to a fuel injector comprising an injector housing having a pressure chamber from which fuel subjected to a high pressure is injected into a combustion chamber of an internal combustion engine when the pressure in a control chamber expands into a pressure relief chamber by a control valve device. The aim of the invention is to create a fuel injector which has a long service life even though subjected to high pressures. To this end, the injector includes a low-pressure supply line which is connected to a low-pressure return line by a purge path extending through the pressure relief chamber.