A recording layer having a recording magnetic domain for recording thereon information is formed. A readout layer for reading the information by the application of a light beam is formed on the recording layer. An intermediate layer made of a film having in-plane magnetization is formed between the recording layer and readout layer to control a magnetic exchange coupling force between the recording layer and readout layer. The readout layer is arranged so that the stable magnetic domain width in the readout layer is larger than that of the recording magnetic domain in the recording layer at room temperature. At a readout temperature achieved by the light beam, the stable magnetic domain width becomes smaller than that of the recording magnetic domain, and the magnetization direction in the recording magnetic domain is copied. Consequently, the information on the recording layer is read only from a section corresponding to a central portion of the light beam through the readout layer by the light beam, and the effect of other magnetic domains adjacent to the magnetic domain to be read in the readout layer can be reduced. It is thus possible to achieve high density recording of information on the recording layer.