Disclosed is a rotor for an electric motor in which permanent magnets can be arranged efficiently. A rotor of the electric motor according to the present invention comprises a rotor core constructed by punching out silicon steel lamination plates into a predetermined shape and laminating a predetermined number of the silicon steel lamination plates; a plurality of cavities provided on the rotor core; flat-shaped permanent magnets having a cross-sectional face made by a long side and a short side, inserted to the cavities; a chamfered portion formed on a portion of, among intersecting points of the long side and the short side of the permanent magnets, at least the intersecting point near an outer peripheral portion of the rotor core.