An epicyclic gear mechanism consisting of a first driven gear, a second driven gear and a rotation regulating member. The first driven gear meshes with a planet gear when the planet gear revolves about a sun gear in one direction and is rotationally driven when the planet gear rotates on its axis in the same position. The second driven gear meshes with the planet gear when the planet gear revolves in the other direction and is rotationally driven when the planet gear rotates on its axis in the same position. The rotation regulating member is actuated by interlocking with the revolving motion of the planet gear. The rotation regulating member regulates the rotation of the second driven gear by engaging with the second driven gear when the planet gear meshes with the first driven gear. The same member regulates the rotation of the first driven gear by engaging with the first driven gear when the planet gear meshes with the second driven gear.