To provide a novel commutator which very much strengthens the fastening force of commutator segments arranged around a holder at equal intervals to be able to endure strong impacts, even without a washer.

The commutator 1 is constituted by arranging a plurality of the commutator segments 3 along the outer periphery of the holder 2 at equal intervals S; and when the commutator segments 3 are attached, a terminal 32 of the commutator segment 3 is set on a recessed bearing surface 23 formed on a flange 22 of the holder 2. The holder 2 and the commutator segment 3 have a locking structure 4, in which part of the holder 2 and that of commutator segment 3 overlap each other on the bearing surface 23, to prevent the movement of the attached commutator segment 3 in the direction of the bearing surface 23. The locking structure 4 includes a dowel 41, formed projecting from the bearing surface 23 and a receiving hole 42, formed on the commutator segment 3 so as to fit the dowel 41. It is preferable that the head of the dowel 41 be thermally welded, after the dowel 41 is fitted in the receiving hole 42.