A fluid flow machine includes a main flow path which is confined by a hub (3) and a casing (1) and in which at least one row of blades (5) is arranged, with a blade end with gap being provided on the blade row, with the blade end and the main flow path confinement performing a rotary movement relative to each other in a vicinity of the blade end, with at least part of the running gap (11) retracted radially from the main flow path confinement into the main flow path, with the running gap (11) at the retractions no longer being confined by the main flow path confinement, but by a peripheral guiding device (10) passed by the main flow and firmly connected to the main flow path confinement and having a row of profiles (12).