A fuel treatment device (2) converts a hydrocarbon-containing fuel into a fuel for a fuel cell (3). The fuel treatment device (2) has for this purpose a mixture formation space (7) for forming and processing a mixture of fuel and another component, a reformer (8) for converting the mixture into a synthesis gas and a desulfurization stage (9) for removing sulfur from the synthesis gas or from the mixture. The reformer (8) and desulfurization stage (9) are arranged adjacent to each other in a housing (10) along an axis of the housing (10).