To provide a commutator for a rotating machine which can prevent floating of a commutator piece even in use at high revolution.

A commutator 61 is equipped with a commutator base 65 made of synthetic resin, a sleeve 67 arranged inside this and set on an armature shaft 41, and many metallic commutator pieces 66 having projections 68 for embedment arranged intervals apart in circumferential direction around the base and projecting toward the side of the sleeve 67. Many sleeve projections 69 projected toward the side of the commutator 66 and having such sectional form that the tips are larger than the bases are provided apart in its circumferential direction around the sleeve 67, and these projections 69 are hooked in the recesses of the base 65, and also the thickness of each part of the base 65 is equalized. As a result, the coupling force among the base 65, the commutator piece 66, and the sleeve 67 is balanced.