A magnetic pole to form at least a part of a stator of a rotary electric machine by a plurality of the magnetic poles being arranged in an annular shape, the magnetic pole comprising: - a core having an arc-shaped yoke portion forming a part of an outer circumferential portion of the stator, a tooth portion projecting from the yoke portion toward a central axis of the stator, and an end portion extending in a circumferential direction of the stator from an end on a central axis side of the tooth portion; - winding frames provided to both ends, in a direction along the central axis, of the core, each of the winding frames having a first thin portion, a second thin portion, and a third thin portion extending in the direction along the central axis, and a projection projecting in the direction; and - sheet-like insulators provided on both sides in the circumferential direction of the tooth portion, wherein each winding frame has: a first flange located on a yoke portion side; a second flange which is located to be opposed to the first flange and has the projection; and a trunk portion provided between the first flange and the second flange, wherein the first thin portion is provided to the second flange of each winding frame, the second thin portion is provided to the first flange of each winding frame, and the third thin portion is provided to the trunk portion of each winding frame, wherein a part of each insulator is held by being sandwiched between the projection and the first thin portion, or a part of each insulator is held by being sandwiched between the projection and the third thin portion, wherein of a surface part of the core that faces a space adjacent in the circumferential direction to the tooth portion, parts (43A, 42A, 41A) in contact with the first, second and third thin portions (13A, 12A, 11A) are recessed by an amount corresponding to a thickness of each of the first, second and third thin portions (13A, 12A, 11A) as compared to the rest of the surface part. - a core having an arc-shaped yoke portion forming a part of an outer circumferential portion of the stator, a tooth portion projecting from the yoke portion toward a central axis of the stator, and an end portion extending in a circumferential direction of the stator from an end on a central axis side of the tooth portion; - winding frames provided to both ends, in a direction along the central axis, of the core, each of the winding frames having a first thin portion, a second thin portion, and a third thin portion extending in the direction along the central axis, and a projection projecting in the direction; and - sheet-like insulators provided on both sides in the circumferential direction of the tooth portion, wherein each winding frame has: a first flange located on a yoke portion side; a second flange which is located to be opposed to the first flange and has the projection; and a trunk portion provided between the first flange and the second flange, wherein the first thin portion is provided to the second flange of each winding frame, the second thin portion is provided to the first flange of each winding frame, and the third thin portion is provided to the trunk portion of each winding frame, wherein a part of each insulator is held by being sandwiched between the projection and the first thin portion, or a part of each insulator is held by being sandwiched between the projection and the third thin portion, wherein of a surface part of the core that faces a space adjacent in the circumferential direction to the tooth portion, parts (43A, 42A, 41A) in contact with the first, second and third thin portions (13A, 12A, 11A) are recessed by an amount corresponding to a thickness of each of the first, second and third thin portions (13A, 12A, 11A) as compared to the rest of the surface part. wherein each winding frame has: a first flange located on a yoke portion side; a second flange which is located to be opposed to the first flange and has the projection; and a trunk portion provided between the first flange and the second flange, wherein the first thin portion is provided to the second flange of each winding frame, the second thin portion is provided to the first flange of each winding frame, and the third thin portion is provided to the trunk portion of each winding frame, wherein a part of each insulator is held by being sandwiched between the projection and the first thin portion, or a part of each insulator is held by being sandwiched between the projection and the third thin portion, wherein of a surface part of the core that faces a space adjacent in the circumferential direction to the tooth portion, parts (43A, 42A, 41A) in contact with the first, second and third thin portions (13A, 12A, 11A) are recessed by an amount corresponding to a thickness of each of the first, second and third thin portions (13A, 12A, 11A) as compared to the rest of the surface part.