A multilayered optical disk an information recording method and information reproducing method utilizing the disk includes three or more recordable or rewritable information recording layers, which has, among the plurality of information recording layers, at least a first recording layer and a second recording layer located on a side nearer to a light incident surface than the first recording layer, and which respectively has a first test area configured by a plurality of segments in the first recording layer, a second test area configured by a plurality of segments in the second recording layer, and comprising a specific area in which there is recorded information used to determine whether or not the respective segments in the first test area can be used.