An armature is provided with: a core having a plurality of teeth radially disposed about a rotary shaft; a plurality of coils wound around each set, where two or more teeth serve as one set; a shaft passing through the center of the core; and a commutator that is fixed to the shaft and rotates together with the armature. The plurality of coils have a plurality of inner coils that are arranged at the rotary shaft side of the teeth, and a plurality of outer coils that are arranged outside of the inner coils. The plurality of inner coils are annularly arranged in such a way that adjacent inner coils are not wound around the same tooth. The plurality of outer coils are annularly arranged in such a way that adjacent outer coils are not wound around the same tooth. The outer coils are wound around teeth of a combination that is different from the combination of teeth around which the inner coils are wound. The commutator is divided into the same number of segments as the inner coils or the outer coils.