and the guide member 102 has an axial length b the distance a and the length b are related to each other by a b 0 1 1 since the retainer nut 106 is stopped by the shoulder 101b when the guide member 102 is positioned between the upper end of the boss 107 and the lower end of the retainer nut 106 there is a gap of about 0 1 mm created between the guide member 102 and the boss 107 and the retainer nut 106 the ultrasonic tape guide 200 has a flat laminated ultrasonic vibrator 104 fixed to the guide member 102 as shown in fig6 the ultrasonic vibrator 104 comprises a plate like piezoelectric element 104c of ceramics and a pair of electrodes 104a 104b attached respectively to opposite sides of the piezoelectric element 104c a lead 103a is connected to the electrode 104a and a lead 103b is connected to the electrode 104b as shown in fig5 the guide member 102 has a flat outer circumferential surface 102a and the ultrasonic vibrator 104 is fixedly mounted on the flat surface 102a the ultrasonic vibrator 104 can be expanded and contracted in the axial direction of the guide member 102 as indicated by the arrows the support teeth 105a 105b are positioned on the main shaft 101 as follows when an alternating voltage is applied from a driver circuit not shown to the ultrasonic vibrator 104 through the leads 103a 103b the ultrasonic vibrator 104 vibrates the guide member 102 in a pattern indicated by the standing wave shown in fig3 the guide member 2 and.