A fastening element (12) for fastening a filter sector (9) of a filter disc in a disc filter to a support sleeve (8) in a shaft (1) of the disc filter. The fastening element (12) comprises a clamp element (13) and a support bar (16) arranged in connection with the clamp element (13), whereby the support bar (16) is arranged to be fastened to the filter sector (9) of the filter disc, and the clamp element (13) is arranged to be fastened to the support sleeve (8) in the disc filter shaft (1) to fasten the filter sector (9) of the filter disc to the disc filter shaft (1). Further, a fastening arrangement for fastening a filter sector (9) of a filter disc in a disc filter to a support sleeve (8) in a disc filter shaft (1).
