A fastening device for furniture fittings on furniture parts which includes at least one dowel core that can be inserted into a hole of a furniture part. The dowel core can be arranged inside a dowel sleeve, and an actuating device moves the dowel sleeve relative to the dowel core, so that the dowel sleeve spreads on the dowel core. The dowel core and the dowel sleeve have at least two, preferably more, corresponding inclined surfaces that are offset in the axial direction, so that if the dowel sleeve is moved relative to the dowel core, the dowel sleeve spreads substantially evenly at two, preferably more, axially offset locations.