An apparatus on a textile machine for cleaning fibre has a high-speed first roller conveying a fibre web, and second and third rollers. Second roller is arranged downstream of third roller and so co-operates with first roller, that fibre is detached, the fibre is transferred to nip, with third roller and is conveyed by third roller to nip with first roller where it is transferred back to the first roller. A separating knife is arranged downstream of the second roller. In order to improve the degree of cleaning between separating knife and the nip of first roller with second roller there is a separation opening of width about from 40 to 60 mm.