A stator for a rotary electric machine comprising: a plurality of core segments that each have a circular arc-shaped back yoke portion and a tooth, said plurality of core segments being arranged into an annular shape by butting together circumferential side surfaces of said back yoke portions; a cylindrical frame into an inner circumferential side of which said plurality of core segments that are arranged into said annular shape are inserted and held; first and second insulators (10, 10a) that each have a trunk portion and first and second flange portions (12, 13) that are linked to two longitudinal ends of said trunk portion, said first and second insulators (10, 10a) being disposed such that bottom surfaces of said trunk portions are placed alongside two axial end surfaces of said tooth such that longitudinal directions of said trunk portions are aligned with a radial direction of said tooth and said first flange portions are oriented radially inward; a concentrated winding coil that is configured by winding a conductor wire around said tooth for multiple laps so as to pass through a concave space that is formed by said trunk portions and said first and second flange portions (12, 13) of said first and second insulators (10, 10a); and insulating papers that are disposed between two circumferential side surfaces of said tooth and said concentrated winding coil, wherein: a crossover point of said conductor wire is formed on a coil end of said concentrated winding coil that is positioned above said first insulator; slot-housed portions of said concentrated winding coil that are positioned on two circumferential sides of said tooth are configured such that said conductor wire is arranged in a staggered stacking pattern in multiple rows and in multiple layers; and characterized in that a varnish is applied to said coil end that is positioned above said first insulator, and a varnish groove is formed on an inner peripheral surface of said second flange portion and an upper surface of said trunk portion so as to extend from axially outside to a lower portion of an innermost layer of said coil end to which said varnish is applied. a plurality of core segments that each have a circular arc-shaped back yoke portion and a tooth, said plurality of core segments being arranged into an annular shape by butting together circumferential side surfaces of said back yoke portions; a cylindrical frame into an inner circumferential side of which said plurality of core segments that are arranged into said annular shape are inserted and held; first and second insulators (10, 10a) that each have a trunk portion and first and second flange portions (12, 13) that are linked to two longitudinal ends of said trunk portion, said first and second insulators (10, 10a) being disposed such that bottom surfaces of said trunk portions are placed alongside two axial end surfaces of said tooth such that longitudinal directions of said trunk portions are aligned with a radial direction of said tooth and said first flange portions are oriented radially inward; a concentrated winding coil that is configured by winding a conductor wire around said tooth for multiple laps so as to pass through a concave space that is formed by said trunk portions and said first and second flange portions (12, 13) of said first and second insulators (10, 10a); and insulating papers that are disposed between two circumferential side surfaces of said tooth and said concentrated winding coil, wherein: a crossover point of said conductor wire is formed on a coil end of said concentrated winding coil that is positioned above said first insulator; slot-housed portions of said concentrated winding coil that are positioned on two circumferential sides of said tooth are configured such that said conductor wire is arranged in a staggered stacking pattern in multiple rows and in multiple layers; and characterized in that a varnish is applied to said coil end that is positioned above said first insulator, and a varnish groove is formed on an inner peripheral surface of said second flange portion and an upper surface of said trunk portion so as to extend from axially outside to a lower portion of an innermost layer of said coil end to which said varnish is applied. a crossover point of said conductor wire is formed on a coil end of said concentrated winding coil that is positioned above said first insulator; slot-housed portions of said concentrated winding coil that are positioned on two circumferential sides of said tooth are configured such that said conductor wire is arranged in a staggered stacking pattern in multiple rows and in multiple layers; and characterized in that a varnish is applied to said coil end that is positioned above said first insulator, and a varnish groove is formed on an inner peripheral surface of said second flange portion and an upper surface of said trunk portion so as to extend from axially outside to a lower portion of an innermost layer of said coil end to which said varnish is applied.