To provide a simplified clutch device providing a turn-on operation based on worker's intention and an automatic turn-off operation subsequent to the turn-on operation, and restoring a predetermined stopping position when the automatic turn-off operation is performed.

The clutch device is made up by combining a driven wheel 20 provided with a cutout portion 20A whose radius R1 partially decreases, a driving roller 10 for friction-driving the driven wheel 20, and a positioning cam mechanism 30 for positioning the stopping position of the driven wheel 20. The torque from the driving roller 10 is blocked automatically in a position of the cutout portion 20A of the driven wheel 20 for positioning. The stopped driven wheel 20 stopped restarts from the cutout portion 20A by a temporary manual operation for pressing the driving roller 10 against the cutout portion 20A.