Provided is a stator structure comprising a stator core (104) having a multiplicity of concave slots (105) and a multiplicity of convex magnetic poles (106) alternately in the circumferential direction, and a magnet wire (101) of a rectangular transverse section having an insulating cover film (103) formed on the outer circumference of a metal wire (102). A spacing size (W<SUB>2</SUB>) between the two side faces (109, 109) of the slot (105) is formed to become smaller from a bottom portion (107) toward a leading end opening (108) of the slot (105). The magnet wire (101) is wound on the magnetic pole (106) and inserted in a laminar shape into the slot (105), and is arranged such that its width size (W<SUB>1</SUB>) is reduced continuously or stepwise from the bottom portion (107) toward the leading end opening (108) of the slot (105).
