To provide a rotating shuttle of a bobbin idle preventing type which can not only prevent decrease in frictional force over a long period of use but also easily set the desired frictional force.

This rotating shuttle has a bobbin made of a magnetic substance such as iron and a bobbin case having a magnet on its surface making contact with the bobbin, with three magnets 8 embedded in the closing lid part 3 of the bobbin case 1 of a fully rotating shuttle used in a normal sewing machine; i.e., predetermined resistance that is semipermanently invariable to the rotation of the bobbin used is given so that idling of the bobbin is prevented by replacing the bobbin case 1 with that used in a fully rotating shuttle used in normal sewing machines.