A rotation transmission mechanism includes a drive shaft, a drive gear, a pinion gear, a first bearing, and a positioning structure. The drive shaft is rotatable with respect to a chassis. The drive gear is unitarirlotya table with the drive shaft. The pinion gear is rotatably mounted to the chassis and disposed in a skew direction to the drive shaft, the pinion gear meshed with the drive gear. The first bearing is mounted to the chassis, is disposed between the chassis and the drive shaft, and rotatably supports the drive shaft. The positioning structure is mounted to an end of the drive shaft, and positions the drive shaft with respect to the first bearing.
