1. A motor comprising: a stationary portion including a stator; and a rotating portion including a rotor magnet, and rotatably supported by the stationary portion through a lubricating oil; wherein the stationary portion includes: a shaft portion including a central axis extending in a vertical direction as a center thereof; a lower plate portion arranged to extend radially outward from a lower portion of the shaft portion; and an outer tubular portion arranged to extend upward from an outer edge portion of the lower plate portion; the rotating portion includes: a sleeve portion arranged to have the shaft portion inserted therein, and including one communicating hole arranged to extend completely there through from an upper surface to a lower surface thereof; and a cover portion arranged to extend radially outward from the sleeve portion; an outer circumferential surface of the shaft portion and an inner circumferential surface of the sleeve portion are arranged to together define a first gap therebetween, and an inner circumferential surface of the outer tubular portion and an outer circumferential surface of the sleeve portion are arranged to together define a second gap therebetween; a channel including the first gap, the second gap, and the communicating hole is filled with the lubricating oil; the cover portion includes a hole portion defined therein, an axial extension range of the hole portion being arranged to overlap with an axial extension range of the communicating hole in a radial direction; a center of the hole portion is arranged on a plane including the central axis and a center of the communicating hole, and the communicating hole and the hole portion are arranged on opposite sides of the central axis; and the following inequality is satisfied: V 2 <(σ 1 /σ 2 )·V 1 where σ 1 is a density of the sleeve portion, V 1 is a volume of the communicating hole, σ 2 is a density of the cover portion, and V 2 is a volume of the hole portion.