PURPOSE: To prevent spark from being generated between brushes and commutators by providing an armature winding except rectified ones, with a current passage, among armature windings to be connected to commutator segments positioned between the brushes adjacent to each other.

CONSTITUTION: Between a + side commutation improving brush 10 set on the rotation-directional side of a shaft 1 to a + side brush 7, and a - side brush 8, a first current passage 14 is set, and to the current passage 14, a capacitor 12 for permitting current to flow in the direction of the + side commutation improving brush 10 from the - side brush 8 and permitting the current hardly to flow in the counter direction, is connected. In the meantime, between a -side commutation improving brush 11 set on the rotation-directional side of the shaft 1 to the - side brush 8, and the + side brush 7, a second current passage 15 is set, and to the current passage 15, a capacitor 13 for permitting current to flow in the direction of the + side brush 7 from the - side commutation improving brush 11 and permitting the current hardly to flow in the counter direction, is connected.