To provide an electromagnetic clutch equipped with an engagement type clutch mechanism which has a large power transmission force while keeping high mechanical strength of a rotor and an armature.

The electromagnetic clutch includes: the rotor 6, the armature 32, and a tooth ring 23 (engaging member) made of a non-magnetic material fixed on the rotor 6. The tooth ring 23 includes: an annular body 23a and a plurality of projections 23c, which are formed so as to project from the annular body 23a toward end surface of the armature 32 and arranged circumferentially in the annular body 23a. The annular body 23a is inserted in an inside annular groove 12a formed on the end surface of the rotor 6. A plurality of recessed portions 28 which the projections 23c can engage with are formed on the end surface of the armature 32.