A magnetic medium using spin-polarized electrons, and an apparatus and method of recording data on the magnetic medium are provided. The magnetic medium includes a polarization layer and a magnetic recording layer. The polarization layer spin-polarizes electrons. In the magnetic recording layer, the direction of magnetization varies depending on the direction of the spin-polarization of the electrons. The data recording apparatus includes a light source and a probe. The light source radiates circularly polarized light, and the probe injects electrons spin-polarized by the circularly polarized light into a magnetic medium and changes the direction of the magnetization of the magnetic medium to record data on the magnetic medium. Because the direction of magnetization is adjusted using spin-polarized electrons, fast data recording can be achieved.