A driving device comprising: a motor and a magnetic clutch, the magnetic clutch comprising: a first rotating member driven so as to rotate; an armature member being movable in an axial direction thereof together with the first rotating member and being rotatable integrally with the first rotating member; a second rotating member facing the armature member in the axial direction thereof and being rotatable relative to the armature member; a magnetic force generating means for generating a magnetic force by being energized, the magnetic force being used for attracting the armature member toward the second rotating member in order to establish a connection between the armature member and the second rotating member so as to be integrally rotatable; a sensor magnet fixed to the second rotating member for generating a magnetic field that changes in a circumferential direction of the sensor magnet; a sensor provided so as to face the sensor magnet in order to detect a change of the magnetic field; and a fixing member formed with a first claw portion characterized in that the fixing member further comprises a second claw portion, the first claw portion engaged with the second rotating member while being press-fitted thereto in a radial direction thereof and the second claw portion engaged with the sensor magnet while being press-fitted thereto in a radial direction thereof; wherein the sensor magnet is fixed to the second rotating member by means of the fixing member. a motor and a magnetic clutch, the magnetic clutch comprising: a first rotating member driven so as to rotate; an armature member being movable in an axial direction thereof together with the first rotating member and being rotatable integrally with the first rotating member; a second rotating member facing the armature member in the axial direction thereof and being rotatable relative to the armature member; a magnetic force generating means for generating a magnetic force by being energized, the magnetic force being used for attracting the armature member toward the second rotating member in order to establish a connection between the armature member and the second rotating member so as to be integrally rotatable; a sensor magnet fixed to the second rotating member for generating a magnetic field that changes in a circumferential direction of the sensor magnet; a sensor provided so as to face the sensor magnet in order to detect a change of the magnetic field; and a fixing member formed with a first claw portion characterized in that the fixing member further comprises a second claw portion, the first claw portion engaged with the second rotating member while being press-fitted thereto in a radial direction thereof and the second claw portion engaged with the sensor magnet while being press-fitted thereto in a radial direction thereof; wherein the sensor magnet is fixed to the second rotating member by means of the fixing member. a first rotating member driven so as to rotate; an armature member being movable in an axial direction thereof together with the first rotating member and being rotatable integrally with the first rotating member; a second rotating member facing the armature member in the axial direction thereof and being rotatable relative to the armature member; a magnetic force generating means for generating a magnetic force by being energized, the magnetic force being used for attracting the armature member toward the second rotating member in order to establish a connection between the armature member and the second rotating member so as to be integrally rotatable; a sensor magnet fixed to the second rotating member for generating a magnetic field that changes in a circumferential direction of the sensor magnet; a sensor provided so as to face the sensor magnet in order to detect a change of the magnetic field; and a fixing member formed with a first claw portion characterized in that the fixing member further comprises a second claw portion, the first claw portion engaged with the second rotating member while being press-fitted thereto in a radial direction thereof and the second claw portion engaged with the sensor magnet while being press-fitted thereto in a radial direction thereof; wherein the sensor magnet is fixed to the second rotating member by means of the fixing member.