A fluid flow machine includes at least one casing 1 and at least one rotor drum 3 rotatable about a machine axis 4, with stator vanes 8 and rotor blades 7 being arranged in an annulus duct 2 formed between the casing 1 and the rotor drum 3 The annulus duct 2 is divided into an outer annular duct 5 and an inner annular duct 6 by at least one annular flow divider 11, in each of which rotor blades 7 and stator vanes 8 are arranged Outer rotor blades 7a, which are arranged in the outer annular duct 5, are rotatable at a different speed than the inner rotor blades 7b, which are arranged in the inner annular duct 6.