PURPOSE: To enable ternary recording, by using an organic high molecular weight substance as a recording material using a combination of three states of the substance, namely, a non-changed state, a phase changed state and a bit or recess formed state.

CONSTITUTION: A recording medium comprises a base 1 and a recording layer 2 provided on one side of the base. The recording layer 2 consists essentially of a polymer blend and a light-absorptive substance. When the medium is irradiated with a laser beam with low power, the light-absorptive substance generates heat to raise the temperature of the polymer blend to a temperature not lower than the clouding point, causing a state change, whereby only the part irradiated with the laser becomes cloudy. When the medium is irradiated with a laser beam with high power, the polymer blend in contact with the light-absorptive substance is heated to a high temperature, whereby it is evaporated or deformed, resulting in that a pit or recess is formed at the part irradiated with the laser beam. The polymer blend may be, for example, a blend of polystyrene with polyvinyl methyl ether, a blend of polyvinylidene fluoride with polymethyl acrylate, or a blend of polypropylene oxide with polybutadiene.