Fuel cell unit (2, 28) comprising - a plurality of fuel cells assembled to form a block, - an axial longitudinal duct (6, 8, 30) running past the fuel cells for supplying the fuel cells with operating gas - connecting passages (12, 14, 44, 46, 60) which connect the axial longitudinal duct (6, 8, 30) to the fuel cells and are implemented with different flow resistances (R hydr,9, R hydr,13) according to their longitudinal position in the longitudinal duct (6, 8, 30), wherein the connecting passages (12, 14, 44, 46, 60) each comprise the same number of radial channels connected in parallel and are formed by stamping a metal sheet of a bipolar plate, and the setting of the flow resistances (R hydr,9, R hydr,13) is established by a different number of opened radial channels, wherein the opening of the radial channels is implemented in each case by a hole in the metal sheet and the number of opened radial channels is determined by the number of holes, - and another axial longitudinal duct (6, 8, 30) connected to the fuel cells by connecting passages (12, 14, 44, 46, 60), characterised in that - the axial longitudinal duct (6, 8, 30) and the other axial longitudinal duct (6, 8, 30) are each implemented as a sack-shaped axial duct, - the axial longitudinal duct (6, 8, 30) and the other axial longitudinal duct (6, 8, 30) are each connected to the fuel cells such that the operating gas is passed through the fuel cell unit via the two longitudinal ducts (6, 8, 30) and the fuel cells in a U-shaped manner, and - the flow resistances (R hydr,9, R hydr,13) are set via the radial channels of the connecting passages (12, 14, 44, 46, 60) such that during operation the static pressure differences in the fuel cells connected to the longitudinal duct (6, 8, 30) are at least essentially equal, and the flow resistances first continuously decrease over the length of the longitudinal duct (6, 30) in the flow direction and then increase again. - a plurality of fuel cells assembled to form a block, - an axial longitudinal duct (6, 8, 30) running past the fuel cells for supplying the fuel cells with operating gas - connecting passages (12, 14, 44, 46, 60) which connect the axial longitudinal duct (6, 8, 30) to the fuel cells and are implemented with different flow resistances (R hydr,9, R hydr,13) according to their longitudinal position in the longitudinal duct (6, 8, 30), wherein the connecting passages (12, 14, 44, 46, 60) each comprise the same number of radial channels connected in parallel and are formed by stamping a metal sheet of a bipolar plate, and the setting of the flow resistances (R hydr,9, R hydr,13) is established by a different number of opened radial channels, wherein the opening of the radial channels is implemented in each case by a hole in the metal sheet and the number of opened radial channels is determined by the number of holes, - and another axial longitudinal duct (6, 8, 30) connected to the fuel cells by connecting passages (12, 14, 44, 46, 60), - the axial longitudinal duct (6, 8, 30) and the other axial longitudinal duct (6, 8, 30) are each implemented as a sack-shaped axial duct, - the axial longitudinal duct (6, 8, 30) and the other axial longitudinal duct (6, 8, 30) are each connected to the fuel cells such that the operating gas is passed through the fuel cell unit via the two longitudinal ducts (6, 8, 30) and the fuel cells in a U-shaped manner, and - the flow resistances (R hydr,9, R hydr,13) are set via the radial channels of the connecting passages (12, 14, 44, 46, 60) such that during operation the static pressure differences in the fuel cells connected to the longitudinal duct (6, 8, 30) are at least essentially equal, and the flow resistances first continuously decrease over the length of the longitudinal duct (6, 30) in the flow direction and then increase again.