PURPOSE: To suppress the vibration of a brush and reduce arc discharges by composing a brush arm part of a highly conductive metal thin film of several microns thickness which can supply required minimum current to the brush and a vibration insulator.

CONSTITUTION: A sheet material 5 made of rubber vibration insulator or non- rubber system resin which is soft and has good absorbing property is attached to a brush 4. The surface of the sheet material 5 is coated with a highly conductive metal (Ag, Al, Cu and etc.) thin film formed by sputtering. With this constitution, a brush which can follow the brushed surface very wall can be obtained and the arc discharges created between the brush 4 and a commutator 7 by the vibration of the brush 4 can be reduced so that the wear of the brush 4 and noises created between the brush 4 and the commutator 7 can be reduced.