A commutator comprises a plurality of segments 10 arranged annularly and insulated from each other, the segments 10 being integrally held on a base 41 formed by molding a synthetic resin material, and risers 20 arranged along the outer peripheral edges of the respective segments 10 and connected to the terminals 52 of respective coiled wires, a stepped section 30 being formed at the boundary of the segments 10 and the risers 20, so that the upper surfaces 22 of the risers is axially recessed from the brush contact surface 12 of the segment 10. With a commutator having the above described configuration, the segments can be separated from each other by forming slits only in the segment section that is the upper portion of the stepped section formed between the segment section and the riser section of a blank. Thus, the length of each slit that has to be cut is reduced to by turn reduce the time required for the cutting. Bosses are formed in the inner space of the stepped section to reinforce the segments and enhance the mechanical strength of the segments.