In the stator of a electric rotary machine in which heat conductive insulation resin is filled at the end portions of a stator coil, the material of a stator core, the stator coil, the heat conductive insulation resin and a frame is selected such that a linear thermal expansion coefficient α1 of the stator core, a linear thermal expansion coefficient α2 of the stator coil, a linear thermal expansion coefficient α3 of the heat conductive insulation resin being filled and a linear thermal expansion coefficient α4 of the frame satisfy a relation that α1