The invention provides an alternating current commutator motor. A housing of the alternating current commutator motor has an outer shell and an end cover. A cross section where the outer shell and a shaft center cross has an open part. The end cover covers the open part. One of the outer shell and the end cover has a plurality of cutting protrusion parts. The cutting protrusion parts extend in an installation direction in which the end cover is installed on the outer shell. Each cutting protrusion part comprises a top end part which is cut into more than two portions in the installation direction. The other of the outer shell and the end cover has a plurality of insertion holes. The plurality of cutting protrusion parts are embedded in the corresponding insertion holes. After the plurality of cutting protrusion parts are embedded in the corresponding insertion holes, a twisting force with the installation direction as an axis is applied to each cutting protrusion part. Meanwhile, each top end is divided into more than two portions. Each divided top end is inclined and falls down in a direction in which the corresponding twisting force is applied.