Electromagnetic spring clutch

An electromagnetic spring clutch includes a stator, an excitation coil, an input-side rotating member, an output-side rotating member, a coil spring, and a rotor. A central hole is formed in the stator. The central hole has an inner circumferential surface formed by a plurality of magnetic pole segments that mesh each other alternately through a gap in circumferential and axial directions. The excitation coil is accommodated in the stator. The input- and output-side rotating members are made of a non-magnetic member and formed with fitting portions and coil tight-winding surfaces. The fitting portions respectively support the two open end portions of the central hole of the stator, and the coil tight-winding surfaces have end portions that oppose each other in the central hole. The coil spring is wound on the coil tight-winding surfaces of the two rotating members and has one end hooked by the input-side rotating member. The other end of the coil spring is hooked by the rotor disposed in the magnetic field of the stator. The rotor is made of a hysteresis material.