The present invention facilitates size and weight reduction by enhancing a coil space factor. A rotating electrical machine according to the present invention is provided with a core having a slot that is continuous in the axial direction, a winding provided within the slot, and an insulating member provided between the slot and the winding and is characterized in that a first pyramid-frustum surface of the insulating member that is provided on the side of the insulating member that is inserted into the slot and/or a second pyramid-frustum surface that is provided on the side of the insulating member into which the winding is inserted is provided at an axial end of the core.