Properties of low‐frequency octupole vibrations built on superdeformed rotational bands are investigated by means of the RPA in a uniformly rotating frame. Large configuration space composed of 9 major shells is used. Numerical examples are presented both for the152Dy and the192Hg regions. We always obtain extremely collective octupole vibrations withK=1, 2 and 3. It is shown that the properties of theK=1 octupole vibrations are especially sensitive to the amount of the static pairing correlations. Microscopic structures of these soft octupole vibrations and their character changes associated with the increase of the Coriolis‐mixing effects are investigated.