Provided are a rotor of a motor capable of attaining a high-speed rotation by appropriately dispersing a stress exerted on a flux barrier portion while reducing a leakage of magnetic flux, and a fan driving motor including the rotor. A second inner wall surface is greater than a first inner wall surface in length in a cross-section perpendicular to a rotational axis (C). A side wall surface has a flux barrier wall surface extending from each of both ends of the second inner wall surface in the cross-section perpendicular to the rotational axis (C), the flux barrier wall surface extending outward relative to the second inner wall surface in an extending direction of the second inner wall surface and more distant from an outer edge of a rotor as it goes from the second inner wall surface toward the first inner wall surface in the cross-section perpendicular to the rotational axis (C).