A flexible resin layer, on the surface of which an uneven pattern corresponding to information to be recorded is formed, and a reflection layer formed on the uneven pattern of the resin layer and having light reflectivity are provided to thereby constitute a flexible optical information recording medium. Further, the resin layer is supported by a flexible supporting layer. For manufacturing such a flexible optical information recording medium, a resin liquid, which can be hardened by irradiation of ultraviolet rays or electron rays, is filled between an ultraviolet ray or electron ray transmissible base film serving as the supporting layer and an uneven pattern original block. Ultraviolet rays or electron rays are then irradiated through the base film to harden and give form to the resin liquid on the base film, thereafter to exfoliate it. For another manufacturing method, a resin layer is formed on an ultraviolet ray or electron ray transmissible base film to form a rolled transfer film. The resin layer surface of the transfer film is pressure-welded onto the surface on which the uneven pattern is formed of the original block while softening the resin layer by heating it so as to transfer the uneven pattern. Ultraviolet rays or electron rays are then irradiated through the base film to harden the resin layer which once has been softened, thus to exfoliate the transfer film from the original block.