An object of the present invention is to promote weight reduction while improving torsional stiffness of a motor case of a rotary electric machine. A motor case accommodates a stator, a rotor facing an inner periphery of the stator, and a rotating shaft coupled to the rotor. The motor case includes a peripheral wall which is formed in a tubular shape and has a space accommodating the stator and the rotating shaft on an inside, a flange portion which is formed at one end of the peripheral wall and is coupled to an outside, and damping ribs which are formed at an outer periphery of the peripheral wall, are formed between a position crossing the outer periphery of the peripheral wall and the flange portion on an extension of the rotating shaft in a radial direction from an end portion of the stator, and are constituted by a plurality of ribs.