Commutator and electric rotary device having the same

The commutator is capable of reducing contact resistance between the brush and a commutator, improving efficiency of an electric rotary device and restricting exhaustion of the commutator. The commutator comprises: a plurality of commutating pieces having outer faces; and a plurality of sliding members fixed on the outer faces of the commutating pieces, the sliding members including carbon nano fibers or carbon nano tubes whose outermost layers have electric conductivity.