Abstract: An optical disk medium in which high density recording/reproducing is possible, an information recording method and an information reproducing method using it are provided. A pit composed of a phase change material and a recording film different from it are provided on an optical disk. The phase change pit has a pattern of a single frequency. A mark having a size on the same level as the phase change pit can be formed by melting a single phase change pit while recording and controlling the optical absorbance and the temperature of the recording film at the region. A single phase change pit is molten while reproducing. Since the optical characteristics of the molten region are different from the optical characteristics of other regions, only data at the molten region can be reproduced by a super-resolution effect.