Abstract: A rotating electrical machine including a stator core formed by layering electromagnetic steel sheets, a first insulator and a second insulator facing with each other and fitted to the stator from an axial direction of the stator core, and a coil winding formed by resin molding and wound around the first and the second insulators. The first insulator includes a first end portion and a first side wall portion and the second insulator includes a second end portion and a second side wall portion. A gap is formed between the first and the second side wall portions and is positioned at a first end portion side or a second end portion side from a middle position of the length of the stator core in the axial direction and is positioned at a portion of the coil winding where a curvature thereat is larger than that at the middle position.