To provide a rotation transmitting device employing a mechanical frictional resistance applying means using centrifugal force instead of an electromagnetic means using a magnetic suction force.

A cylindrical surface 2a is formed on the inner diameter of an outer ring 2, an input shaft 4 is rotatably engaged with the inside of it, a plurality of cam surfaces 6 forming a wedge space are formed on the input shaft 4 between it and the cylindrical surface 2a. A holder 7 stored between the facing surfaces of the outer ring 2 and the input shaft 4 incorporates a roller 9 engaging with the cylindrical surface 2a and the cam surfaces 6 by relative rotation of the outer ring 2 and the input shaft 4, and has the frictional resistance applying means comprising a two-way clutch C having a switch spring 12 for holding the roller 9 at a neutral position, an armature 13 mounted to the end of the holder 7 unrotatably relatively to the holder 7, the end face 13b and a tilting surface 16 gradually approaching the radial outside facing to this, and a plurality of weights 19 stored between the end face 13b and the tilting surface 16.