Abstract: The invention relates to a side channel compressor having an impeller (2) which is arranged rotatably in the housing (1) of the compressor and has a carrying ring (3) which is provided with feed vanes (4) and, at least on one side, projects axially beyond a hub part (5) which bears the carrying ring and connects it to a drive shaft, in the case of which compressor, in the region of the carrying ring (3), a sealing ring (6), which butts against the inner circumference of the axially projecting part of the carrying ring (3) and seals the gap (13) present between the impeller (2) and the housing (1), is retained, by means of a retaining ring (8), in a state clamped against an abutment surface provided on the housing (1). The installation is simplified in that a centering border (10) which aligns the sealing ring (6) is provided on the abutment surface.