The present invention relates to a storage medium (10) comprising an information layer (11) including transparent and non-transparent areas in which the information is stored, and a magnetizable layer (12) intended to contain at least one magnetized area, which is temporarily created when a light spot is transmitted by a corresponding transparent area of the information layer. The present invention also relates to a reading device for reading information on such a storage medium (10). Said reading device comprises an optical element (23) for generating an array of light spots from an input light beam (21), a light spot being intended to temporarily create the magnetized area in the magnetizable layer (12) when passing through the corresponding transparent area of the information layer (11), and a magnetic sensor (24) comprising an array of sensor elements for detecting the at least one magnetized areas.