An automotive rotary electric machine stator comprising: a stator core that includes: a cylindrical core back portion; a plurality of tooth portions that are arranged in a row circumferentially such that each extends radially inward from an inner circumferential surface of said core back portion; and a plurality of slots that are bounded by said core back portion and said tooth portions; and a stator winding that is mounted onto said stator core, wherein: said stator winding is constituted by distributed windings that include: slot-housed portions (10a, 10b) that are housed in each of said slots; and coil end portions that link together end portions of said slot-housed portions (10a, 10b) that are housed in pairs of said slots that are separated by a predetermined number of slots, said coil end portions extending outward in two circumferential directions from each of said slots; said slot-housed portions (10a, 10b) and root portions of said coil end portions that connect to said slot-housed portions (10a, 10b) are formed so as to have flat cross sections; and said slot-housed portions (10a, 10b) are housed inside said slots in contact with each other so as to line up radially in at least one column; characterized in that flatnesses of root portions of said coil end portions that are radially adjacent and that extend outward in different circumferential directions from said slots are mutually different, wherein the flatness is determined by dividing a length of the long sides of rectangular cross sections by a length of the short sides of the rectangular cross sections, and the longitudinal axes of the flat cross sections of the slot-housed portions (10a, 10b) lined up radially in a column are oriented circumferentially or the longitudinal axes of the flat cross sections of the slot-housed portions (10a, 10b) lined up radially in a column are oriented radially. a stator core that includes: a cylindrical core back portion; a plurality of tooth portions that are arranged in a row circumferentially such that each extends radially inward from an inner circumferential surface of said core back portion; and a plurality of slots that are bounded by said core back portion and said tooth portions; and a cylindrical core back portion; a plurality of tooth portions that are arranged in a row circumferentially such that each extends radially inward from an inner circumferential surface of said core back portion; and a plurality of slots that are bounded by said core back portion and said tooth portions; and a stator winding that is mounted onto said stator core, wherein: said stator winding is constituted by distributed windings that include: slot-housed portions (10a, 10b) that are housed in each of said slots; and coil end portions that link together end portions of said slot-housed portions (10a, 10b) that are housed in pairs of said slots that are separated by a predetermined number of slots, said coil end portions extending outward in two circumferential directions from each of said slots; said slot-housed portions (10a, 10b) and root portions of said coil end portions that connect to said slot-housed portions (10a, 10b) are formed so as to have flat cross sections; and said slot-housed portions (10a, 10b) are housed inside said slots in contact with each other so as to line up radially in at least one column; characterized in that said stator winding is constituted by distributed windings that include: slot-housed portions (10a, 10b) that are housed in each of said slots; and coil end portions that link together end portions of said slot-housed portions (10a, 10b) that are housed in pairs of said slots that are separated by a predetermined number of slots, said coil end portions extending outward in two circumferential directions from each of said slots; slot-housed portions (10a, 10b) that are housed in each of said slots; and coil end portions that link together end portions of said slot-housed portions (10a, 10b) that are housed in pairs of said slots that are separated by a predetermined number of slots, said coil end portions extending outward in two circumferential directions from each of said slots; said slot-housed portions (10a, 10b) and root portions of said coil end portions that connect to said slot-housed portions (10a, 10b) are formed so as to have flat cross sections; and said slot-housed portions (10a, 10b) are housed inside said slots in contact with each other so as to line up radially in at least one column; characterized in that flatnesses of root portions of said coil end portions that are radially adjacent and that extend outward in different circumferential directions from said slots are mutually different, wherein the flatness is determined by dividing a length of the long sides of rectangular cross sections by a length of the short sides of the rectangular cross sections, and the longitudinal axes of the flat cross sections of the slot-housed portions (10a, 10b) lined up radially in a column are oriented circumferentially or the longitudinal axes of the flat cross sections of the slot-housed portions (10a, 10b) lined up radially in a column are oriented radially.