PURPOSE: To obtain an optical recording medium capable of recording and reproducing with ease and also recording with high density in a high speed, by using a shape memory alloy as the recording medium.

CONSTITUTION: A shape memory alloy film 23 consisting of, for example, an Ni-Ti alloy is formed on a disc substrate 21 through a buffer layer 22 by the vacuum deposition method or the like. The shape memory alloy 23 is held in the martensite phase state, and a part of it is deformed by, for example, press work to form a projecting part 24. A semiconductor laser light 25 is condensed to a beam having a diameter a little less than 1μm and is irradiated to this optical disc to raise the temperature locally, then, the projecting martensite phase part 24 is transformed to an austenite phase flat part at about 80°C, and thus, data is recorded. In case of reproducing, a laser light is irradiated, and data is repro duced in accordance with a difference between quantities of reflected light in the projecting part and the flat part.