the magnetic force of the magnet 13 on the main member 2 or 88 with traveller setter holding travellers in the above way the guide seat 8 of the main member 2 or 88 is placed on the upper surface of a ring flange 114 of a spinning machine in such a fashion that the surface of the guide seat is level as shown in fig1 a at this time the undersurface of the ring flange contacting part 56 of the bar 54 for determining position is contacted with the upper surface of the ring flange 114 so that the traveller setter can be easily leveled then by pulling the case 6 or 100 the projection 9 of the main member 2 or 88 makes contact with the inner surface of the ring flange and the setting member 4 or 94 which is moved relative to main member 2 by the working member 7 moves rearward and downward being guided on the cam followers 10 in the guide grooves 30 as shown in fig1 b and a leg end of the traveller 111 is pressed by the hook 23 and engaged with the inside of the ring flange if the case 6.