A method for recording and reproducing information on or from an optical recording medium, which comprises:recording information by illuminating light to the optical recording medium which is equipped as a recording film with a thin film comprising dispersed fine grains of a material capable of showing a metal-insulator transition to cause the metal-insulator transition owing to the heating effect of the light; and reproducing the information by utilizing changes in optical characteristics owing to a plasma resonance absorption by the fine grains dispersed in the thin film. The method of this invention permits high-density recording with high sensitivity and upon reproduction, enables reproduction of record with a high signal/noise ratio. The recording medium obtained by this method is an erasable optical recording medium, which permits its reutilization for recording and reproduction after erasure of the previously-stored record.