the fitting holes 16 as shown in the first embodiment as shown in fig4 the supporting shaft x is fitted into the fitting hole o and the driven gear 2 and the rack r are engaged when the lid c rotatably provided with respect to the housing h is rotated in an opening or closing direction opening and closing operations of the lid c can be braked at a desired torque thus damper effect can be provided to the opening and closing operations of the lid c incidentally in the first embodiment described above although the grooves 3d are formed on the circular fitting dent 3 and grooves 12d are provided to the supporting shaft 12 in case either the grooves 3d or the grooves 12d are provided the same effect can also be obtained also although the circular fitting dent 3 is provided in the rotating member 1 and the supporting shaft 12 is provided in the fixed member 11 the supporting shaft may be provided in the rotating member and the circular fitting dent may be provided in the fixed member further although the outer cylindrical projection 5 and the inner cylindrical partition wall 13 are discontinuously formed either the outer cylindrical projection 5.