A stator includes an annular stator core having slots formed therein, a stator coil received in the slots, and insulating sheets each being interposed, in a corresponding one of the slots, between the stator coil and an interior wall surface of the stator core defining the corresponding slot. Each of the insulating sheets includes a sheet-like substrate and a resin layer provided on an outer surface of the substrate. The resin layer is formed of a curable and foamable resin that is foamed and cured by external stimulation. Each of the insulating sheets has an extension portion located outside the corresponding slot and extending nonparallel to an axial direction of the stator core so as to face an axial end face of the stator core. In each of the insulating sheets, the resin layer is provided, on the outer surface of the substrate, in a region including the extension portion.