An information recording layer on a substrate provides a method of recording information by selectively opening the rings of dicyclopentadiene skeletons, thus recording information by forming cyclopentadiene skeletons. The information recorded by the method can be erased by the cycloaddition of cyclopentadiene skeletons. Information can also be recorded or erased by incorporating or eliminating a metal ion from a selectively opened section of a ring of a dicyclopentadiene skeleton after forming an organic thin film comprising the dicyclopentadiene skeleton. Alternatively, after the formation of an organic thin film comprising a cyclopentadiene skeleton, a heterocycle or a benzene ring, a metal ion is incorporated or eliminated from a section between at least two rings of the cyclopentadiene skeleton, the heterocycle or the benzene ring. Thereafter, a metallocene skeleton or a skeleton analogous to the metallocene skeleton is formed or eliminated, thus recording or erasing information. The selective opening of a section of a dicyclopentadiene skeleton ring is carried out by heat or light. The readout of the information is performed by recognizing the cyclopentadiene skeleton, the metallocene skeleton, the skeleton analogous to the metallocene skeleton or the metal atom. The information recording layer of the invention is a chemically adsorbed monomolecular film with a thickness at the angstrom