A rotating electrical machine (10) has a rotor (11), which rotates about an axis (13) and is surrounded concentrically by a stator (12) having a stator winding (30) inserted into a stator body (21), the stator winding (30) including, in a concentric arrangement, a lower layer (16), which is more remote from the axis, and an upper layer (17), which is closer to the axis, of axially extending winding bars (14), which emerge from the stator body (21) at the ends of the stator (12) and are arranged, within an end winding (15), with their bar ends (23), on two concentric circles in pairs one above the other in the radial direction. With such a machine, simplified production of the stator winding (30) with, at the same time, a high dielectric strength is achieved by virtue of the fact that in those winding bars (14) of a pair which belong to different phases within a phase segregation, radial spreading (18) of the bar ends (23) is provided so as to increase the radial distance between the different phases.