NOVELTY - The machine has a rotating portion supported to be rotatable with respect to a stationary portion. A shaft is arranged to extend along a central axis extending in a vertical direction. A bearing portion is arranged to support the shaft such that the shaft is rotatable. An armature is arranged radially outward of rotor magnets. A rotor core (632) includes a through-hole group (640, 644a-644j) extending through the rotor core in an axial direction. The through-hole group is arranged to be unsymmetrical with respect to any imaginary plane that includes a central axis (609).    USE - Rotary electric machine i.e. motor, for use in power-assisted bicycles, electric motorcycles, electric wheelchairs, automobiles, lawn mowers and pressure washers. Can also be used for a generator for wind power generation.    ADVANTAGE - The machine allows press fitting of the shaft into the rotor core to coincide with direction of stamping in press working of the rotor core, so that the machine reduces stresses that are applied to the rotor core and the shaft at the time of the press fitting even if inner edge portions of the upper and lower surfaces of the rotor core have undergone slight deformations during the stamping process, thus enabling the machine to smoothly press-fit the shaft into the rotor core and preventing damage during the press fitting, and hence improving positional accuracy, dimensional accuracy and rotational accuracy of the shaft. The through-hole group is unsymmetrical with respect to any imaginary plane including the central axis, so that the through-hole group on upper and lower surfaces of the rotor core when viewed in the axial direction do not coincide with each other, thus enabling a manufacturer to distinguish between the upper and lower surfaces of the rotor core when assembling the motor.    DESCRIPTION OF DRAWING(S) - The drawing shows a top view of a rotor core.    Equiangular positions (P1-P10)    Central axis (609)    Rotor core (632)    Through-holes (640, 644a-644j)