Abstract: The present invention provides a diesel filter system and a fuel heating device comprising a PTC heating element and a rod-shaped heat conductor which is in thermal contact with PTC heating element. The rod-shaped heat conductor comprises at least two tubular parts arranged in parallel. The PTC heating element is located between said at least two tubular parts. The system and device according to the invention is of compact constructional design and can therefore be installed in different kinds. The invention increases the rate of flow and allows for a high heat transfer from the PTC heating element to fuel.