The invention relates to a fixture (30) for a polishing or scouring disk of a floor cleaning machine. Said fixture (30) comprises a base plate (32) that can be connected to a driving disk (42) of the floor cleaning machine. The driving disk (42) can be rotated about an axis of rotation and supports a retaining part that is provided with retaining wings (48, 49, 50) which are disposed at a distance from the base plate and extend radially outward. In order to further develop said fixture so as to reduce the risk of the retaining wings being damaged when the polishing or scouring disk is worn, the retaining part is fitted with a supporting wall (46) in a zone surrounded by the retaining wings, at least some areas of said supporting wall (46) protruding past the retaining wings in an axial direction relative to the axis of rotation.