A stator core has a laminated core, and a polyphase stator winding installed in slots at a predetermined slot pitch, the laminated core being formed into an annular shape by forming a main laminated body by laminating a number of main lamination plates, forming a laminated body by laminating an end plate having higher rigidity than the main lamination plates onto one end surface of the main laminated body, disposing the polyphase stator winding in the slots, and placing end portions of the laminated body in contact with each other by bending the laminated body such that opening portions of the slots are on an inner circumferential side.