To provide an electromagnetic clutch mechanism, excellent both in seizure resistance performance and saturation magnetic flux density, in which manufacturing is easy.

This electromagnetic clutch mechanism comprises clutch plates 2 and 3, and an excitation coil 9 to generate attracting force between the clutch plates 2 and 3 to be applied to each other. At least one of the clutch plates 2 and 3 is composed of cast iron material, and for the cast iron material, nodular iron is employed, or otherwise, cast iron material in which ferrite in texture is parted, with setting of a ferrite ratio at 50% or more and 80% or less employed. Its magnetic characteristics and friction coefficient can be kept high, while generation of seizure is restricted. Cast iron material has high moldability, and high magnetic characteristics. Depending on the state of the ferrite composition in the texture, generation quantity of seizure (abrasion) is varied.